Project SEKAI: Memories Across the SEKAI

Players travel between the SEKAI worlds, meet residents among 26 main Project SEKAI characters who appear as NPCs, and recover memories through a six-chapter campaign. Choices made along the way change later dialogue, four variants of the final scene can be found, and a post-story epilogue titled Voice Remembers becomes available. Following Miku's fading signal drives the story, and each world reacts as the story progresses, with wounded places healing and residents slowly returning.

Card collection is a second layer. Players build a collection that is saved outside Minecraft storage, and cards become usable items: a right-click on a physical card activates a balanced skill with a cooldown. Teams of up to five cards can be assembled, with up to three teams, and the same card cannot occupy several slots inside one team. The SEKAI are available from the start, without finishing the story. The mod is published for Forge and NeoForge, targets 1.21.1 only, and is released under the MIT License, but it is not open source. The server and every player need the mod installed.