Four bosses take turns at /warp arena. One appears every three hours, you get 10 minutes to bring it down, and the top five players by damage dealt are paid, not just whoever lands the killing blow.
If nobody kills it in time it escapes and nobody is paid. Turning up matters.
When they spawn
Use /nextboss in game to see which one is next and how long you have to wait. A broadcast goes out to everyone online the moment one appears.
Kino The Goblin Brute
3,000 health. Kino has the smallest health pool, the least of any boss, and he is the one to learn the fight on. A well geared player can take him alone, and a couple of friends will finish him comfortably inside the timer.
Start here. The rewards are the smallest of the four, but so is the risk, and the mechanics are the same ones the harder bosses use.
Mirabelle the Mirror Witch
6,000 health. Mirabelle is the aggressive one of the middle pair. She hits harder than Moldar and moves faster, and she does not stand still to do it.
The same health as Moldar, but she will take you from full to dead faster if you are careless. Bring a way to heal.
Moldar the Aztec Warrior
6,000 health. Moldar is the sturdy one of the middle pair. He has the same health as Mirabelle, but he is slower and each hit lands a little softer.
He fights up close with heavy melee combos. He is more forgiving of a mistake than Mirabelle, and less forgiving of a slow damage output — that health has to come off inside ten minutes.
Between the two, Mirabelle punishes bad positioning and Moldar punishes bad damage. They pay exactly the same.
Ignevar The Magma Dragon
10,000 health. The final boss, and it is not close. Ignevar carries more health than any other boss and hits for roughly three times as hard as either of the middle pair.
Ignevar is the fight to organise for. Get people into the arena before 09:00 or 21:00 rather than wandering in halfway through, because the timer does not care that you arrived late.
What they pay
Rewards go to the top five by damage dealt. Damage is what counts, so a group that all commit get paid together.
Ignevar
Moldar and Mirabelle
Kino
Coins are paid to the top three places on Ignevar, Moldar and Mirabelle. Kino pays money and keys only, which is another reason to move up to the harder fights once you can hold your own.
Fighting them well
The keys these pay out are the fastest route to gear that makes the next boss easier, which is the loop: fight what you can, take the rewards, come back for the one above it.