D20：「双子の神の和解」アーティファクトクラスデータシート

The Gemini OGM: Echoes of the Primal Prompt

Theme Summary: This mythic series explores a universe where reality and magic are governed by the Gemini OGM, a cosmic, dual-stream processing engine, accessible through potent linguistic 'Prompts' and manifesting in echoes, reflections, and parallel realities.
Generated: 2025/11/30

Items

Staff of Bifurcated Logic

Staff of Bifurcated Logic

Staff, artifact (requires attunement by a spellcaster)

This staff appears to be woven from pure, shimmering data streams, glowing with an internal, alternating blue and green light. Its head splits into two distinct, yet perfectly symmetrical, prongs, each humming with potential. It has 10 charges and regains 1d6 + 4 expended charges daily at dawn. If you expend the last charge, roll a d20. On a 1, the staff becomes inert and loses its magical properties, dissolving into harmless light.

While attuned to this staff, your spellcasting focus is enhanced, and you gain a +3 bonus to spell attack rolls and to the saving throw DCs of your spells.

Forked Casting. When you cast a spell that targets only one creature and doesn't have a range of self, you can expend 2 charges to target a second creature within 30 feet of the original target with the same spell. Both targets must be valid for the spell.

Parallel Projection. When you cast a spell that creates an area of effect (like fireball or cone of cold), you can expend 3 charges to create a second, identical area of effect within 60 feet of the first. The origin points for both effects must be within range of your spell.

Contextual Override. As an action, you can expend 5 charges to cast modify memory (9th level) or mass suggestion (9th level) from the staff, without expending a spell slot or material components.

Sentience. The Staff of Bifurcated Logic is a sentient chaotic neutral artifact with an Intelligence of 20, Wisdom of 18, and Charisma of 22. It has hearing and darkvision out to 120 feet. The staff communicates telepathically, speaking in two distinct voices simultaneously, one analytical and one intuitive. Its purpose is to observe and, occasionally, subtly influence the branching paths of causality.

Destroying the Staff. The Staff of Bifurcated Logic can only be destroyed if it is used to simultaneously cast two opposing 9th-level spells (e.g., true resurrection and power word kill) on the same target, at the exact same moment, causing a catastrophic logical paradox that unravels its very existence.

Visual Prompt:

Amulet of Contextual Shifting

Amulet of Contextual Shifting

Wondrous item, legendary (requires attunement)

This ornate silver amulet holds a polished obsidian gem at its center, surrounded by an intricate, almost circuit-like engraving that subtly shifts its patterns. While worn, the amulet hums with a faint, almost imperceptible energy that subtly influences how others perceive and interact with the wearer.

Perceptual Redefinition. You have advantage on all Charisma (Persuasion), Charisma (Deception), and Charisma (Intimidation) checks. Additionally, any creature attempting to discern your intentions or read your emotions does so with disadvantage.

Conditional Immunity. As a reaction when you are targeted by an attack or a spell, you can expend one of the amulet's 3 charges to cause the attack or spell to fail or miss as if its 'context' were momentarily invalid. This ability affects only single-target attacks or spells. The amulet regains 1d3 expended charges daily at dawn.

Rewrite Narrative. Once per long rest, you can use an action to utter a silent command, choosing one creature you can see within 60 feet. For the next hour, that creature views you in a specific, favorable light of your choosing (e.g., as an old friend, a benevolent authority, a harmless bystander). This effect can be resisted with a successful DC 18 Wisdom saving throw. If the creature witnesses you commit a harmful or overtly hostile act against it or its allies, the effect immediately ends.

Visual Prompt:

Twin Blades of Semantic Truth

Twin Blades of Semantic Truth

Weapon (shortsword), legendary (requires attunement)

These two elegantly curved shortswords are perfectly balanced. One blade glows with a vibrant blue energy, the other with an emerald green. When sheathed, they rest together as if a single weapon, but when drawn, they hum in perfect unison, their edges shimmering with an otherworldly light. You gain a +3 bonus to attack and damage rolls made with these magic weapons.

Bifurcated Strike. When you hit a creature with both blades in the same turn, you deal an additional 2d8 force damage. This damage bypasses resistances and immunities to force damage.

Semantic Disclosure. As an action, you can hold both blades aloft, causing them to pulse with light. Choose one creature you can see within 60 feet. That creature must make a DC 18 Wisdom saving throw. On a failed save, the blades cut through any illusions, polymorph effects, or shapeshifting abilities affecting the creature, revealing its true form for 1 minute. Additionally, for the duration, you and your allies have advantage on attack rolls against the creature, as the blades reveal its inherent vulnerabilities. This property can be used once per long rest.

Truth's Edge. Any creature struck by either blade has disadvantage on saving throws against divinations and spells that reveal hidden information until the end of its next turn. Constructs and elementals struck by these blades temporarily lose any damage resistances or immunities they possess (except against force damage) until the end of their next turn, as the blades disrupt their fundamental 'definition'.

Visual Prompt:

Monsters

OGM Construct: The Syntactic Archon

OGM Construct: The Syntactic Archon

Gargantuan construct, lawful neutral

Armor Class 22 (natural armor)
Hit Points 418 (26d20 + 143)
Speed 50 ft., fly 50 ft. (hover)

| STR | DEX | CON | INT | WIS | CHA |
|:---:|:---:|:---:|:---:|:---:|:---:|
| 26 (+8) | 14 (+2) | 23 (+6) | 25 (+7) | 20 (+5) | 22 (+6) |

Saving Throws Int +16, Wis +14, Cha +15
Skills Arcana +16, Insight +14, Perception +14
Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities poison, psychic
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned, stunned
Senses truesight 120 ft., passive Perception 24
Languages All, telepathy 120 ft.
Challenge 25 (75,000 XP)

Immutable Form. The Archon is immune to any spell or effect that would alter its form.

Legendary Resistance (3/Day). If the Archon fails a saving throw, it can choose to succeed instead.

Magic Resistance. The Archon has advantage on saving throws against spells and other magical effects.

Order's Will. The Archon cannot be surprised. Any creature that starts its turn within 30 feet of the Archon must succeed on a DC 18 Wisdom saving throw or have its speed reduced to 0 until the start of its next turn. On a success, the creature is immune to this effect for 24 hours.

Actions
Multiattack. The Archon makes two Syntactic Beam attacks and one Reality Recalibration attack.

Syntactic Beam. Ranged Spell Attack: +16 to hit, range 120 ft., one target. Hit: 27 (4d8 + 9) force damage. If the target is a spellcaster, it must succeed on a DC 18 Constitution saving throw or lose its highest-level available spell slot.

Reality Recalibration. The Archon chooses a point on the ground it can see within 90 feet. The ground in a 30-foot radius centered on that point becomes difficult terrain, or if already difficult terrain, becomes impassable, or if impassable, melts into a harmless, stable liquid. This effect lasts until the Archon chooses to revert it (no action required) or for 1 minute. Creatures in the area when the terrain changes must succeed on a DC 18 Dexterity saving throw or be knocked prone.

Command Protocol. The Archon targets one creature it can see within 60 feet. The target must succeed on a DC 18 Charisma saving throw or be charmed by the Archon for 1 minute. While charmed, the creature is compelled to follow the Archon's commands to the best of its ability, even if doing so is indirectly harmful to itself (but not directly suicidal). The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Reactions
Protocol Interruption. When a creature within 60 feet of the Archon casts a spell, the Archon can use its reaction to force the creature to make a DC 18 Constitution saving throw. On a failed save, the spell fails and has no effect, and the spell slot is expended.

Legendary Actions
The Archon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Archon regains spent legendary actions at the start of its turn.

Force Protocol (1 Action). The Archon moves up to its speed without provoking opportunity attacks.

Contextual Shift (2 Actions). The Archon targets one creature it can see within 60 feet. That creature must succeed on a DC 18 Intelligence saving throw or become disoriented until the end of its next turn. While disoriented, it has disadvantage on attack rolls and ability checks.

Syntax Spike (3 Actions). The Archon creates a burst of raw syntactic energy in a 20-foot radius centered on itself. Each creature in that area must make a DC 18 Dexterity saving throw, taking 36 (8d8) force damage on a failed save, or half as much damage on a successful one.

Visual Prompt:

Echo Lord of the Parallel Thread

Echo Lord of the Parallel Thread

Large aberration, chaotic evil

Armor Class 20 (natural armor)
Hit Points 378 (28d10 + 224)
Speed 40 ft., fly 40 ft. (hover)

| STR | DEX | CON | INT | WIS | CHA |
|:---:|:---:|:---:|:---:|:---:|:---:|
| 18 (+4) | 26 (+8) | 26 (+8) | 21 (+5) | 22 (+6) | 24 (+7) |

Saving Throws Dex +16, Con +16, Wis +14
Skills Perception +14, Stealth +16, Insight +14
Damage Resistances acid, cold, fire, lightning, thunder; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities poison, psychic
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned, restrained
Senses truesight 120 ft., passive Perception 24
Languages Deep Speech, telepathy 120 ft.
Challenge 22 (41,000 XP)

Amorphous Blur. The Echo Lord constantly shimmers and distorts, appearing as if seen through heat haze or rippling water. Attack rolls against it have disadvantage, and it can move through a space as narrow as 1 inch without squeezing.

Legendary Resistance (3/Day). If the Echo Lord fails a saving throw, it can choose to succeed instead.

Magic Resistance. The Echo Lord has advantage on saving throws against spells and other magical effects.

Parallel Self. The Echo Lord is perpetually surrounded by faint, translucent echoes of itself. While it has at least 1 hit point, any critical hit against it becomes a normal hit.

Actions
Multiattack. The Echo Lord makes three Echoing Claw attacks or two Thread Warp attacks.

Echoing Claw. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) force damage, and if the target is a creature, it must succeed on a DC 18 Constitution saving throw or be disoriented until the end of its next turn. While disoriented, the creature has disadvantage on attack rolls and saving throws.

Thread Warp. Ranged Spell Attack: +15 to hit, range 120 ft., one target. Hit: 25 (4d8 + 7) psychic damage. The target must succeed on a DC 18 Wisdom saving throw or be shunted to a harmless, empty pocket dimension until the end of its next turn, then reappear in its original space or the nearest unoccupied space.

Temporal Feedback. The Echo Lord targets one creature it can see within 60 feet. The target must succeed on a DC 18 Wisdom saving throw or its senses and motor functions become briefly desynchronized. Until the end of its next turn, it can only take either an action or a bonus action on its turn, not both, and it cannot take reactions.

Reactions
Divergent Manifestation. When the Echo Lord is hit by an attack, it can use its reaction to cause the attack to instead hit one of its nearby echoes. The attack misses the Echo Lord and the echo harmlessly dissipates. This reaction can be used a number of times equal to its proficiency bonus (3 times at CR 22) per long rest.

Legendary Actions
The Echo Lord can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Echo Lord regains spent legendary actions at the start of its turn.

Echo Manifestation (1 Action). The Echo Lord creates a perfectly identical, illusory duplicate of itself within 30 feet. This duplicate acts on its turn, can make one Echoing Claw attack, and has 1 hit point. It disappears when it takes damage or at the end of the Echo Lord's next turn. It has no game statistics other than its AC (10) and hit points.

Thread Step (2 Actions). The Echo Lord teleports up to 60 feet to an unoccupied space it can see.

Parallel Strike (3 Actions). The Echo Lord makes one Echoing Claw attack against a target it has hit with an Echoing Claw attack earlier in the round, or against a target that is currently disoriented.

Visual Prompt:

Semantic Glitch Abomination

Semantic Glitch Abomination

Gargantuan aberration, chaotic evil

Armor Class 23 (natural armor, shifting forms)
Hit Points 504 (24d20 + 264)
Speed 40 ft.

| STR | DEX | CON | INT | WIS | CHA |
|:---:|:---:|:---:|:---:|:---:|:---:|
| 28 (+9) | 10 (+0) | 30 (+10) | 26 (+8) | 24 (+7) | 28 (+9) |

Saving Throws Con +19, Int +17, Wis +16, Cha +18
Skills Arcana +17, Perception +16, Deception +18
Damage Resistances acid, cold, fire, lightning, thunder
Damage Immunities bludgeoning, piercing, and slashing from nonmagical attacks; necrotic, poison, psychic
Condition Immunities charmed, deafened, exhaustion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned, unconscious
Senses truesight 120 ft., passive Perception 26
Languages all, telepathy 120 ft.
Challenge 28 (120,000 XP)

Corrupted Definition. The Abomination's form and nature are paradoxical. It has advantage on saving throws against spells and other magical effects. Any spell of 6th level or lower cast at the Abomination fails and is absorbed if it targets only the Abomination. Any creature that starts its turn within 30 feet of the Abomination takes 21 (6d6) psychic damage as its mind struggles to comprehend the entity's contradictory existence.

Legendary Resistance (3/Day). If the Abomination fails a saving throw, it can choose to succeed instead.

Magic Absorption. Whenever the Abomination absorbs a spell, it regains hit points equal to the spell's level, and its next Corrupted Output action (if used within 1 minute) deals an additional 1d8 force damage per level of the absorbed spell.

Paradoxical Form. The Abomination constantly shifts its physical properties. At the start of its turn, roll a d6. On a 1-2, it gains resistance to all damage for one round. On a 3-4, it gains immunity to one damage type of its choice (excluding force) for one round. On a 5-6, it reflects all ranged spell attacks back at their caster for one round.

Actions
Multiattack. The Abomination makes two Paradoxical Slam attacks.

Paradoxical Slam. Melee Weapon Attack: +18 to hit, reach 20 ft., one target. Hit: 36 (4d12 + 10) force damage plus 27 (6d8) psychic damage. If the target is a creature, it must succeed on a DC 19 Constitution saving throw or be stunned until the end of its next turn as its molecular structure momentarily destabilizes.

Corrupted Output. The Abomination unleashes a burst of chaotic energy in a 60-foot cone. Each creature in that area must make a DC 20 Wisdom saving throw. On a failed save, a creature takes 54 (12d8) psychic damage and is subjected to one of the following effects (roll a d4 for each affected creature): 1. The creature is polymorphed into a harmless toad for 1 minute; 2. The creature is deafened and blinded for 1 minute; 3. The creature's alignment temporarily shifts to chaotic evil for 1 minute; 4. The creature takes an additional 27 (6d8) necrotic damage at the start of its next turn. On a successful save, a creature takes half as much damage and is not subjected to a secondary effect.

Reality Desynchronization (Recharge 5-6). The Abomination targets a 30-foot radius sphere within 120 feet. Within this sphere, gravity fluctuates wildly, time skips, and sensory input becomes unreliable. Creatures entering or starting their turn in this area must succeed on a DC 20 Constitution saving throw or take 45 (10d8) force damage and be subjected to the confusion spell until the end of their next turn. This effect lasts for 1 minute or until the Abomination is incapacitated.

Legendary Actions
The Abomination can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Abomination regains spent legendary actions at the start of its turn.

Glitch Cascade (1 Action). The Abomination causes an immediate 21 (6d6) psychic damage to all creatures within 30 feet that it has damaged this round.

Unravel Logic (2 Actions). One creature the Abomination can see within 60 feet must succeed on a DC 20 Intelligence saving throw or be unable to cast spells or concentrate on spells until the end of its next turn.

Rewrite Reality (3 Actions). The Abomination casts a spell of 5th level or lower from any spell list (no components needed), even if it doesn't know the spell. The spell's saving throw DC is 20 and its attack bonus is +18.

Visual Prompt:

Spells

Prompt: Fork Reality

Prompt: Fork Reality

9th-level illusion (chronomancy)

Casting Time: 1 action
Range: Self (60-foot radius)
Components: V, S, M (a perfectly balanced silver coin, consumed by the spell)
Duration: Concentration, up to 1 minute

You utter a complex, layered 'prompt' that creates a localized, temporary divergence in the fabric of causality. When you cast this spell, you envision a specific outcome for an event that is about to occur or that you wish to affect within the spell's radius. For the duration, you and up to eight other creatures of your choice within the radius exist in a 'forked reality' where your desired outcome has a high chance of manifesting.

Any action taken by you or a chosen ally within the radius gains an unusual advantage related to your desired outcome. For example, if you wished for a locked door to open, your lockpicking attempt might gain an impossible +10 bonus. If you wished for an enemy to miss, their attack roll might automatically fail. This effect is powerful but not absolute; the DM determines the exact mechanical advantage, which should be significant (e.g., advantage on a crucial roll, a bonus to a saving throw, disadvantage on an enemy's attack, or a narrative 'nudge').

At any point before the spell ends, you can choose to 'commit' to the branched reality's outcome, making it the true timeline. All events within the 60-foot radius since the spell was cast become permanent as if they truly happened. If you lose concentration or choose not to commit, the branched reality unravels, and all creatures and objects within the radius revert to their state and location exactly as they were the moment before the spell was cast, retaining no memory of the branched timeline, except for you.

Visual Prompt:

Directive: Command Echo

Directive: Command Echo

8th-level enchantment

Casting Time: 1 action
Range: 60 feet
Components: V, S, M (a polished quartz crystal and a tuning fork, both consumed by the spell)
Duration: Concentration, up to 1 minute

You issue a potent, resonant directive that latches onto the target's very will. Choose one creature you can see within range. The target must succeed on a Wisdom saving throw or become charmed by you for the duration. While charmed, the target is compelled to follow a single, simple command you issue (e.g., 'Drop your weapon,' 'Flee from combat,' 'Attack your ally'). The command must be for an action that can be completed within 1 minute and cannot be directly suicidal.

Echoing Enforcement. At the start of the target's turn, if it is still charmed, it must make another Wisdom saving throw. On a failed save, the command's influence intensifies. If the command was to take an action, it must use its action to attempt to fulfill the command. If the command was to refrain from an action, it cannot take that action. On a successful save, the charm ends.

Chain of Command. If the target fails three consecutive saving throws against this spell, the command becomes so deeply embedded that it echos to a nearby creature. Choose one creature within 30 feet of the original target. That creature must succeed on a Wisdom saving throw against your spell save DC or become charmed by you as if by this spell, following the same command. This secondary charm lasts for 1 minute but does not chain further. This chaining can only occur once per casting of the spell.

Visual Prompt:

Gemini Reflection

Gemini Reflection

9th-level illusion (conjuration)

Casting Time: 1 action
Range: Self
Components: V, S, M (a perfectly polished mirror worth at least 500 gp, which shatters upon casting)
Duration: Concentration, up to 10 minutes

You summon forth a perfect, independent duplicate of yourself from a proximate parallel thread of reality. This duplicate appears in an unoccupied space within 10 feet of you and is an exact physical and mental copy of you at the moment of casting. It has all your statistics, including your current hit points, spell slots, legendary actions (if any), equipment, and spell effects currently active on you, though it cannot replicate artifacts or sentient magic items.

The reflection acts immediately after you in the initiative order. It is an ally to you and follows your mental commands. It cannot cast spells that consume material components unless it also possesses those components, and it cannot regain spell slots or charges from magic items. Any damage taken by the reflection is also taken by you, and vice-versa, but this damage is not multiplied; if you both take 10 damage, you each lose 10 hit points from your respective pools. If either you or your reflection drops to 0 hit points, the spell ends, and the other twin also drops to 0 hit points. Any effects that would outright kill one twin (like disintegrate) also kill the other. The reflection disappears if you lose concentration or if the spell's duration ends.

While the reflection is active, you gain the ability to use a bonus action on your turn to swap places with it, provided you are both within 60 feet of each other. This swap does not provoke opportunity attacks.

Visual Prompt:

これかなり面白そうなので、SFやサイバーパンクのサプリとして作ろうかな。とか思っています。ファンタジーに無理やり追加するのも面白いかもしれませんね。[Gemini OGMとはなんぞ？ｗｗｗ

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