Sephiria Co

Sephiria supports online co-op for up to four players, with item trading and reviving. It is a genuinely different game with a group — but there are three things worth knowing before you organise a session, and one of them is a limitation TEAM HORAY has publicly acknowledged rather than fixed.

Getting into a game

Two routes:

Public lobbies. Create or browse from the multiplayer UI. A refresh button was added in patch 0.10.5. The lobby list shows each room's game version.

Private lobbies. Steam friend invite, or a join code. You read the code by interacting with the tablets in the lobby — this is not signposted well and is the most common "where is the code" question.

Everyone gathers in the Assembly Space, which has a training dummy for checking damage. Chat is on Enter.

Progress is per-player, not per-host

This is the good news, and it has been true since patch 0.5.0: "Destiny imprint progress is now individualized." Your stats, your unlocked items, your weapon, your costume and your name all come with you. Sapphire counts persist through multiplayer sessions. Chest of Possibilities rolls and their escalating costs are private per player.

You are not playing on someone else's save. You are bringing your own character into their run.

Chapter gating, and the bugs it caused

You are not supposed to join a lobby ahead of your own story progress, and this has leaked repeatedly:

• 0.11.3 warned that clearing Chapter 5 while still on Chapter 4 could hard-block your progression.
• 0.11.4 auto-reset the bogus Chapter 5 clear record on login.
• 1.0.24 fixed both mismatched-progress invites and a case where a Chapter 5 player was softlocked by clearing the game inside a Chapter 6 lobby.

The practical rule: play with people at a similar chapter. The developer has patched three separate variants of this, which suggests the underlying assumption runs deep in the code.

It also explains the common complaint that public lobbies look empty — rooms only list while the host is still in the lobby, and players may only see lobbies matching their own chapter progress.

How difficulty scales

Originally, monster HP scaled with player count. That was changed: now the monster count increases, and multiplayer monster HP was slightly reduced. That is a meaningfully better design for a game about crowd control — more targets rather than spongier ones.

Hard Mode's Festival of Blood got its own multiplayer scaling in 1.0.21, because enemies healing 15% every time they hit someone does not divide well across four players. Healing effectiveness now runs at 66% with 2 players, 50% with 3, 33% with 4.

The ping problem

This is the honest caveat. TEAM HORAY has stated that Sephiria uses Steam's built-in multiplayer transport, which has a ceiling around 5 Mbps, and that late-game item volume exceeds it. The symptom is ping spikes into the 200–2000 ms range as runs get deep and inventories fill.

Players report it as region-dependent, with European sessions worst, and there are cases of 240 ms between two people on the same local network. There was no complete fix at the time of writing.

If you are planning a long co-op session, this is the thing that will end it — not difficulty.

Other known issues

• Linux / Proton. Players have been unable to create or join rooms under Proton 9. Switching to Proton 10 resolved it.
• Duplicate items not merging. Frequently reported as a co-op bug; it is not. Duplicates only merge and upgrade for players who have taken Wisdom level 10, which unlocks [Unique] Stacking. Without it you simply get two separate copies.
• Kicked players cannot rejoin. Clients now also leave when the host's game ends, and the "Leave Lobby" button is disabled during exploration.

What co-op actually changes about a run

Beyond the obvious: with four players you can trade items, which turns the combo system from a solo lottery into a negotiation. If one player is two artifacts short of a threshold and another is holding a duplicate they cannot use, that trade is worth more than either item's raw stats.

Reviving fallen teammates also changes the risk calculus — a solo mistake ends the run, a co-op mistake costs the group tempo. Groups can afford to take Derangement and Mini Boss nodes that a solo player should skip.

Finding people

Public lobby browsing has the visibility problems described above. The community's recommended route is the Discord's looking-for-group channel, which is where most organised groups actually form.

Not verified

We have no confirmed figure for what the item-trading interface will and will not let you hand over, and no developer statement on whether a transport change is planned. The bandwidth ceiling is quoted from TEAM HORAY's own explanation in the Steam discussions, not inferred from testing.