Team up as Team RWBY
RWBY: Grimm Eclipse is a four-player online co-op hack and slash set in the world of Remnant. You pick one of four characters — Ruby, Weiss, Blake, or Yang — and fight through waves of Grimm in a story that adds new locations, new enemy types, and a villain that does not appear in the show. The combat is fast and crowd-focused, drawing on the style of Dynasty Warriors, while the co-op structure takes cues from Left 4 Dead. Missions carry the story forward with full voiceover from the show's cast alongside new voice talent.
Playing together as a group
Everyone in your group joins online and takes a different member of Team RWBY. Each character has her own unlockable abilities and upgrades, so a group can spread roles across the roster instead of doubling up. Fights are built around clearing large groups of Grimm together, and the mission structure keeps the four of you moving through the same objectives rather than splitting off. Alongside the campaign, there are ranked challenges, unlocks, and achievements to work through as a group.
Horde Mode and what to expect
Horde Mode is the other main way to play together. It uses five maps built around defending security nodes against incoming waves of Grimm, with defense turrets placed into the mix. Two of these maps, Merlot's Lab and Merlot's Island, arrived with later DLC, which also added cosmetic costume packs for Team RWBY and Team JNPR. Expect a linear, mission-driven campaign rather than an open world, and note that all multiplayer is online — there is no local co-op option listed.