How Witchspire co-op works, the best 6-player party composition, and how to host or join a co-op session.

Witchspire supports up to 6 players in online co-op. The party leader hosts the session from the in-game menu; everyone else joins via the Steam friends list or a 6-character code. Co-op works for everything except the tutorial and a few NPC personal quests.
Monster HP scales with party size, but loot drops per kill also scale — so a 6-player coven is the most efficient way to play.
The best 6-player party in Patch 0.1.4:
This composition beats every other combination we tested for raw clear-time on the Spire Arbiter Hard mode.
Only the Mirewarden is a true tank. The Mirewarden’s job is to hold aggro, apply Hagfen Vow on cooldown, and emergency-heal when a party member drops below 30% HP.
Emberkins and Gloamcallers are the main DPS. Stay behind the boss, dodge-roll on telegraph, weave basic attacks between cooldowns.
Threadmaidens stay at mid-range, cast Loom of Names on cooldown, and re-summon Familiars if they die.