Quick Answer
The official English site says co-op supports up to four players and is meant for difficult bosses and shrine floors. Game8’s friend-function coverage adds the practical launch detail that most room setup revolves around room codes, public matching, and simple communication tools like stamps. That gives players a clean rule set: host when you need control, join when you just need clears, and keep the room goal obvious.
What Co-op Is Best For
Harder bosses
The official site explicitly points players toward co-op for bosses that feel rough alone. If solo attempts are wasting time or revives, co-op is the clean fallback.
Shrine-style challenge floors
Co-op matters more when a fight demands safer execution than when you are just overclearing easy story content.
Repeated farm targets
Once everyone in the room wants the same reward, co-op becomes an efficiency tool instead of a social detour.
Room Code vs Matchmaking
| Option | When to use it |
|---|---|
| Room code | Best when you are inviting friends, retrying one exact piece of content, or want the room to stay on one farm target. |
| Public matchmaking | Best when you want a quick fill and do not care who joins as long as the room clears. |
| Friend support and stamps | Useful for basic coordination, but not a substitute for a clear host plan or a prepared build. |
When to Host and When to Join
Host if you need control
Host when the content target matters, when you want to repeat one boss or shrine floor, or when you need to invite a specific group through a room code.
Join if you need speed
Join when your only real goal is faster clears. This is the lower-friction option when you do not need to manage the room yourself.
Switch if the room goal changes
If you want to move from quick public clears into planned farming, stop joining random rooms and host your own code room instead.
Simple Host Checklist
- Pick one target before opening the room.
- Use a room code if you want the same people or the same plan across repeats.
- Bring a build that already clears the content comfortably.
- If runs keep failing, lower greed before blaming the room.
Simple Joiner Checklist
- Join rooms that match content you already clear or nearly clear.
- Assume the room wants stable clears unless the host says otherwise.
- Do not bring a half-built experiment into a farm room.
- If the room is wiping, simplify your setup instead of trying to carry with greed.
What the CBT Report Changes About the Advice
The official CBT feedback report is why this guide stays conservative. Players liked the mutual support of co-op, but the report also mentions performance issues and screens becoming hard to read during busy runs. That makes three habits more important than they might look on paper:
- Clear visual telegraphs beat flashy clutter.
- Low-maintenance damage beats fragile “perfect run” rotations.
- Team-first pacing beats one player greedily forcing the room to carry them.
FAQ
How many players does co-op support?
The official English site says co-op supports up to four players.
Should I use room codes or public matchmaking?
Use room codes when you want control or known teammates. Use public matching when you want quick fills and do not need the room to stay private.
Is it better to host or join?
Host when the target run matters and join when speed matters more. The better option depends on whether control or convenience is the real bottleneck.
Should I use co-op to test new builds?
Usually no. The CBT report’s readability and performance notes are exactly why already-proven builds are safer in shared rooms.