Fighting Game · Guides & deep dives

V2 Sovereign Core

blockstrings, juggle state, damage application, and combat event ordering.

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The V2 sovereign core is the local-only runtime boundary for deterministic gameplay, replay, save compatibility, and platform-cert-sensitive client code. These systems remain in the Unreal project and do not delegate behavior to Oshun services during runtime execution.

Non-Negotiable Local Surfaces#

  • V2Combat: hitbox / hurtbox authority, frame data, collision resolution, blockstrings, juggle state, damage application, and combat event ordering.
  • V2Gameplay: fighter state, GAS-backed attributes, match state transitions, gameplay-affecting save payloads, and deterministic match-start payloads.
  • V2Input: per-platform IMC files, motion input parsing, input buffering, input recording, and local remap application.
  • V2Netcode rollback: rollback simulation, prediction, correction, deterministic frame hashes, rollback snapshots, and peer-synchronized inputs.
  • Save-format binary: binary profile / progression / settings format and all migration readers or writers that can change gameplay-affecting state.
  • Replay container: input stream, frame hash stream, metadata schema, replay verification, and deterministic replay playback.
  • Sequencer timelines: cinematic timing tracks and any combat-affecting timing embedded in authored Level Sequences.
  • Per-platform IMC files: platform-specific input mapping contexts and certification-sensitive defaults.
  • Anti-cheat client driver: client-side anti-tamper integration, local driver policy, signed client package wiring, and platform ban-list intake.

Service Isolation Rule#

No file inside the sovereign core may call out to async Oshun services, import @oshun/* packages, include V2Services/ headers, or depend on network output that can vary per peer during rollback simulation.

The only external data allowed into rollback-synchronized gameplay is data baked into the deterministic match-start payload before frame 0; every peer must receive the same bytes and the payload must be replay-recorded.

Allowed Boundaries#

  • V2Services may consume Oshun gRPC and event-bus data, but sovereign modules cannot link against it.
  • V2Telemetry may observe sovereign results after frames resolve, but it cannot feed data back into frame simulation.
  • Bellona and Hathor may provide cooked assets or compiled data before runtime, but runtime mutation of deterministic state remains V2-local.
  • AI Director, Psyche tendency profile, Iris commentary, and Oshun-sourced behavior hints use the rollback-ignored side-channel defined in rollback-isolation.md.

Review Rule#

Any proposed exception requires an ADR under V2/docs/decisions/ and must keep the deterministic replay hash identical when Oshun services are unavailable.