Animated Lich, Faustus
Faustus was an accomplished magician in life, and in undeath, he seems to be a highly powerful Lich.
The animated Lich, Faustus is using:
<worn on head> a chain cowl <worn on legs> the lower half of a shredded robe <wielded> three juggling fireballs
Faustus wanders, and is too high a level for heroes to see with detect invis, so you'll have to area-spell or let it attack you.
Faustus will sometimes throw the fireballs, and they will blow up, so try to kill it quickly or stun it if you're looking for them.
Walking route from Aelmon: ???.
Walking route from Svlad: Go north, mob wanders, is high level and invisible, so you'll have to area-spell or let it attack you.