The only boss of the challenge is The Immovable, an animated armor with 457 health, 121 attack damage, Magical Attack and Retaliate: Fireball. In addition to these stats, whenever he is reduced to about 90% health, if there is a bloodpool on the map, he will turn the nearest bloodpool to acid, heal, and his attack damage will drop by about 10%.
It is recommended to win this challenge with the Gnome Bloodmage.
This level will be intimidating at first, because you're not allowed any preparations, and there are no altars. This will prevent you from mitigating the Bloodmage's standard weaknesses - low starting Mana, no starting BURNDAYRAZ - by properly selected preparations and/or worship. That said, the challenge can be won relatively consistently if you use a strategy that accepts this. The Gnome is recommended because without using any gods, the Gnome offers by far the strongest Mana spike. The recommended strategy:
1. Before finding BURNDAYRAZ: You will have difficulty killing opponents above your level. So just kill whatever you can, adopting your strategy to the first glyphs you find. Preserve the blood pools unless you can go for a higher-level kill (or find it impossible to take on anything without it). Try to leave 3-4 low-level monsters (not bloodless!) for later. Kill the Cave Snakes before level ups, and ignore the Wraiths unless you can kill them without getting Mana Burned. As BURNDAYRAZ can be anywhere, you may end up exploring most of the map before you conclude this phase.
2. After finding BURNDAYRAZ: With this glyph, your hunting season opens. Now you can kill all the Wraiths with impunity, even those several levels above you, and generally higher-level kills become possible. Using up most of your remaining black space, and most of your blood pools, you should be able to kill enough monsters to reach level 8.
3. Gear up: spend your money on things that give you Mana or Base Damage, or just have good conversion value. If you have more than 2-3 blood pools left, use up the excess. Convert everything except your PISORF and BLUDTUPOWA (and any items still needed, i.e. +Damage items, Mana potions, etc.). One important thing, before moving on to the boss fight, make sure the boss is placed next to another monster (ideally not a Snake). Use a bit of PISORF-ing or teleportation to place him. You can do this already earlier, whenever you have a bit of Mana left.
4. Boss fight: Start PISORF-ing the boss. He may take 20+ castings to die, which is why it's better to push him against another monster rather than a wall. As you run out of Mana, use up your resources to replenish your mana. First, consume any remaining blood pools (this is important as the boss can consume them if you bring him to cca. 90% health). Second, drink your Mana potions, and Health Potions (and use BLUDTUPOWA, it still gives you 1 Mana per casting). Then if you still need to, kill the low-level monsters you left and immediately consume their blood pools (again converting Health into Mana via BLUDTUPOWA). Lastly, you can convert your BLUDTUPOWA for one last Mana Potion if needed. This should be more than sufficient to kill the boss without needing much luck.
The only strategy with which I have been even nearly successful is with a dwarf bloodmage. When I finally defeated him, it was because I got a lucky combination of an Orb of Zot and Midas Gloves before killing any enemies. I saved up using the Midas Gloves until I could purchase the Orb of Zot. I saved all the bloodpools I could and leveled up to level 8. Then I burned all my remaining mana potions and mana PISORFing the boss. Then I converted every excess item I could, and every glyph other than PISORF. I activated the Orb of Zot. Then I began hitting the boss, healing using bloodpools, and using PISORF on him whenever I had maximum mana. When I ran out of bloodpools, I killed any enemies that were weak enough to net me a health gain from their bloodpool, and then converted my PISORF and started using all my health potions. Even so, it took my last potion to be able to kill him.
Here is another strategy: Using gnome convet items to mana potions and PISORF beat the Boss. Don't leave any blood pools to the Boss! Drink health potion then Convet HP to MP by using BLUDTUPOWA (you can gain ONE mana without any uncovers).