How Sephiria Co-op Works
Sephiria has online co-op for up to four players. Here are the rules that catch groups out — revive HP, healing that scales down, and chapter mismatches.
OfficialCurrent for 1.0.29
GamePrimer EditorialUpdated Verified
Online co-op, up to four players, over Steam. It is not a separate mode with its own rules — it is the same run with more rabbits in it. What changes is that healing gets weaker the more of you there are in one Hard Mode modifier, and reviving hands out temporary HP that vanishes the moment your max HP changes.
What the store actually promises
Four players, online, with item trading and reviving. There is no local or split-screen mode listed, and no lobby browser is advertised — co-op is built around inviting people you know through Steam. Steam Cloud and Family Sharing are both supported, and since 1.0.24 the game also publishes Rich Presence to your Steam profile.
The rules that catch groups out
These are the ones that have moved during 1.0, which is exactly why they are worth knowing — a co-op guide written in early August is already describing a different game.
Revive HP is temporary, and it is fragile. When another player revives you, you can end up above your maximum HP. Since 1.0.26 that surplus survives being healed — it used to disappear — but all of it is lost the instant your maximum HP changes. Picking up a Green Heart mid-fight therefore deletes the buffer someone just spent a revive giving you.
Hard Mode healing scales down with party size. The “Blood Festival” modifier reduces healing effectiveness in multiplayer by player count: 66% at two players, 50% at three, 33% at four. A four-stack running Blood Festival is playing with a third of the sustain a solo player has, and that is deliberate rather than a bug.
Chapter progress has to line up. Through 1.0.24 there were several ways for players at different chapters to end up in one lobby and break each other’s progression — including clearing the game from inside someone else’s Chapter 6 lobby while you were still on Chapter 5, which could block your own progression afterwards. Those specific holes are patched, but the underlying expectation stands: play with people at roughly your point in the story.
Chapter 6 multiplayer was unstable until very recently. A game over in Chapter 6 co-op could freeze progression outright. That was fixed in 1.0.29, on 14 August — if your group is on an older build, that bug is still in it.
Things that are simply better in co-op
Not everything is a tax. Reviving means a death is not automatically the end of a run, and item trading means an Artifact that does not fit your grid can go to someone whose grid it does fit — which is the co-op answer to the single hardest decision in the game.
What we are not going to tell you
There is no step-by-step “click here to host” walkthrough on this page. We have not run a four player lobby ourselves, and describing menus we have not opened is how guides end up telling you to press a button that is not there.
What is on this page is what TEAM HORAY has published, and that turns out to be the part nobody else has collected: the actual numbers, and which patch changed them.
Related
- Sephiria Patch Notes — every co-op change, with the announcement it came from
- Sephiria Chapters — why chapter progress matters for who you play with
- Sephiria Beginner Guide — the inventory rules that trading exists to solve
Sources
- OfficialSephiria on Steam — Online Co-op for up to 4 players, Steam Cloud, Family Sharing, full controller support
- Official1.0.21 Hotfix — Hard Mode "Blood Festival" healing scales down by player count (31 Jul 2026)
- Official1.0.24 Update — chapter-progress invite and Chapter 6 lobby progression fixes, Rich Presence (7 Aug 2026)
- Official1.0.26 Update — temporary HP from revives now survives healing but is lost when max HP changes (13 Aug 2026)
- Official1.0.28 hotfix — Chapter 6 multiplayer freeze after a game over, fixed in 1.0.29 (14 Aug 2026)
