ToME: the Tales of Maj'Eyal

I... I don't understand what just happened to my character. I'm so confused.

I had a really amazing run with Alastor Skullkraken the skeleton Arcane Blade, I had reached level 22 or so and I was about to take on Dreadfell, but I thought I'd go to the mark of the spellblaze first, since I had that heart of the sandworm queen I couldn't eat until I corrupted it.

The level was pretty straightforward and not hard at all.

...And then I reached the boss. He proceeded to teleport me into a hell dimension where the entire floor is made of lava and crippled my cooldown times, rapidly exhausting my massive supply of shields and healing spells, and the whole time he was taking virtually no damage from anything. I died the most humiliating death I have ever suffered in any roguelike ever, feeling totally powerless and like the game was tormenting me for its own amusement.

Exactly how powerful are you supposed to be before taking this guy on? Was there some obvious escape I missed? It was listed on the zone difficulty order guide as being just before Dreadfell, but this guy was far more dangerous than that necromancer was on my previous runs!

The "hell dimension" is due to a talent called Fearscape. It's not actually specific to the Grand Corruptor boss; basically any Defiler-based rare/unique/boss enemy can have this. Some notes about Fearscape:
- It's a sustained spell, so using an ability that removes magical effects on the target can end Fearscape early. For most characters, the easiest way to get this is from gloves of dispersion.
- Sustaining Fearscape costs vim each turn. If the enemy runs out of vim, it will end. For antimagic characters, you could try using Mana Clash to remove the enemy's vim.
- Fearscape deals fire damage per turn to everyone who's not a demon, and heals demons for the same amount. Defilers can get a sustain called Flame of Urh'Rok that causes them to be treated as a demon. If you have the same skill, or an item like Khulmanar's Wrath, you will also be healed by the Fearscape.

Fearscape doesn't actually put your skills on cooldown. That was probably another effect like stun and maybe Burning Hex. In general, when you get Fearscaped your goal should be to either remove the sustain or kill the enemy as fast as possible. The longer you stay there, the more health you'll lose.

As for the Mark of the Spellblaze, I typically do Dreadfell level 1-8 first, then do the Mark and Celia's crypt before fighting the Master.

well... i don't know about the requirements of facing him head on but...

there is a way, which involves a summon, and maybe also a lvl5 phase door if necessary.
the idea is to make him waste all his vim on your minions, while you stay out of his range.
ofc, since spells are refunded on kill, you should avoid allowing him a 1-shot-kill.

anothre thing is...
1) fearscape has a range of 5. stay out of it, and you will not be pulled.
2) he has a spell, that make him be treated as a demon.
2.2) fearscape fires heal demons.

Effigy wrote: Fearscape doesn't actually put your skills on cooldown. That was probably another effect like stun and maybe Burning Hex.

Oh I knew that, I guess my phrasing was a little vague. Yeah I'm pretty sure it was burning hex.

Anyway, this is helpful. Suppose I'm really unlucky with items, are there any arcane blade talents I could use, or should I just make sure to avoid being within 5 spaces?

Just burst damage the snot out of him.