Monsters: Dragon Spawns, Goo Blobs, Nagas, Serpents, Warlocks, File:Acid Blob Monster Icon.png Acid Blobs, File:Burn Viper Monster Icon.png Burn Vipers, Vampires. Monster difficulty is 150% on the main map, and 120% in the arena.
Boss: Nine of the regular bosses (all but Bleaty, Firstborn and Medusa), plus Kinissssch (HP 475, ATK 90, Magic Resist 50%, Magical Attack, Corrosive, Death Protection (5), becomes cowardly at 50%)
No altars spawn in the first area unless prepared.
A Hooded Figure will be somewhere in the map. Talk to them to take a one-way trip to the Arena.
The arena has 2 main areas: The Prayer Room and The Arena. The Prayer Room has every altar, each unlockable for 20 gold, except the Pactmaker, who is free.
The arena has three shops which, unlike the rest of the arena, do not respawn each wave. They hold a keg of mana, a keg of health and The Amulet of Yendor. In each of the four corners a monster is spawned. One is level one, one is level three, one is level five, and one is level seven, and they are automatically bloodless.
In the Arena, you will face nine bosses in waves of three. The nine consist of Lord Gobb, Frank the Zombie, Tomithy Longdall, Super Meat Man, Jörmungadnr, Aequitas, The Iron Man, The Tormented One, and The Tower of Goo. After each wave the blackspace in the arena is replenished, (but not the walls of the arena or the prayer zone), and a new wave of bosses and corner monsters will spawn (corner monsters spawn in different locations from previous waves, so you can build them up over multiple waves).
After you defeat the third wave, the blackspace is replenished and Kinisssch shows up on the battlefield, spawning no corner monsters.
Regen-fighting is the word here. Poison is useful, as are mid-battle level-ups using the corner enemies. The piece de résistance in the boss gauntlet is usually the Tower of Goo and its 75% physical resist: you'll need to either save a lot of mana for this battle, or bring a lot of resistance erosion to it. If it's not him it'll be Frank the Zombie, who has high stats and is immune to poison.
Tikki Tribute - Level up fast with catapult tricks. Worship Tikki Tooki in the clean up phase to get poison, then convert to Mystera for the arena. Use poison to kill all of the bosses without special strategies and follow directions for the ones that do. Convert to the Glowing Guardian or Dracul for extra hp and/or mana after you run out of potions.
Orc Rogue/Glowing Guardian - Prepare Glowing Guardian, attack bonus increasers, Patches, and an item that either provides high attack bonus or high conversion rate. Buy and convert all possible items you won't use later (using bonus potions to get an early level catapult), use Absolution ~5 times for some bonus HP. The objective is to get base damage to achievement levels (150+); this makes poisonless regen-fighting a doable strategy.
Half-Dragon - After enough item conversions, the half-dragon can do even more damage per strike than an orc rogue, without HP difficulties, and easily kills bosses with physical or magic resistance. Hit the bosses into each other, or into other enemies; try to hit low damage bosses into high-damage ones to get a head start. Prep the Dragon Shield and do anything that raises resists or base damage, and convert everything you don't need. Prep Binlor (for piety farming, knockback bonus and a bit of magic resist), Dracul (for blood shield mostly, though all of his boons will do you a bit of good), or Taurog (for resists and piety farming); if you don't worship Dracul switch to him in the arena for Blood Shield.
Gorgon - You have to beat the level 3 times to unlock the gorgon, but her incredible ability at regen-fighting makes her extremely suited to beating it again. Worship Binlor while leveling up to farm piety and magic resist, and switch to Dracul in the arena for even more resists.