Fannar

Useful Info

Fannar the Cold-Hearted is a unique cold-themed elf, equipped with a staff of freezing and ring of ice (67%) or staff of cold (33%), as well as a robe of cold resistance. They prefer to stay out of melee combat, summoning ice beasts to distract you while blasting you with Ice Magic.

The difficulty of this fight is determined almost entirely by how much cold resistance you have. If you've got none (or even vulnerability!), you'll probably want to avoid fighting Fannar.
Reading a scroll of silence will disable Fannar's most dangerous abilities, allowing you to engage them in melee in relative safety.
The summoned ice beasts are distractions -- don't waste time killing them off if you don't have to. They'll all vanish as soon as Fannar falls.

Fannar was male before 0.24.
Prior to 0.18, Fannar knew Condensation Shield, before that spell was removed.
Prior to 0.13, Fannar knew Ozocubu's Armour in his 3rd spell slot, and was less willing to use his ice beasts as shields.
Fannar was added in 0.11, and was the first monster to explicitly generate with jewellery.