Raids are the hardest group content in IdleWorlds: a party of players takes on a boss with its own abilities, rotation and resist checks, and everyone brings a role. Since raids launched, the hardest part for many players hasn't been the fight. It's been finding a group at the same time. Scheduled raid nights fix that.
The bosses unlock in order: Ashmaw, Thessaly, Morwenna, then Grimjaw, with Skarth, the Rime Wyrm, open for Practice. Ashmaw needs Combat 40 and is always open. Each later boss needs the previous one cleared on Normal, and Hard mode of a boss needs that same boss cleared on Normal first. Everyone in the group has to meet the requirement, and a win counts for everyone, alive or not.
Loot is weekly. Your first Normal or Hard clear of each boss per week rolls loot for you, and after that the boss is marked as claimed until Monday 00:00 Eastern. You can keep raiding for leaderboard times, and helping a group after you've looted now pays a helper reward: shards, XP potions or a supply cache. Practice never drops loot and doesn't use up your week, so it's the place to learn a fight.
Your role in a raid comes from your skills. Lends turn a crafting or gathering skill into a raid ability, and your lend level is your skill level plus skill gloves, a profession trinket and village buildings. That means the gear you wear for your profession matters in a raid too.
Raid nights are organised in the #raiding channel of the IdleWorlds Discord. Each planned raid gets a post with the boss, the league and the start time in Eastern, plus a sign-up thread: react with a check mark if you're in, or a thinking face if you might be. Every raid is also a Discord event, so you can mark it Interested and get a reminder. The first two raid nights were Grimjaw on Standard and Ashmaw on SSF.
SSF players raid in their own league, against bosses with far less HP, since they can't trade for gear. That made raid results confusing, because an SSF clear time looked like a Standard one. Results in #raid-results now start with [Standard] or [SSF] so each league's times are compared fairly.
If you've never raided, start with an Ashmaw Practice run, read the raid boss page on the wiki, and sign up for the next raid night. Raid nights are open to everyone who meets the boss's requirement, newer players included.