Thoth Amon is a powerful spellcaster, and is definitely hard for the unprepared. He can curse your items, destroy your armor, and even summon nasties, making facing him head-on in melee a bad idea, especially without magic resistance. Like all @, Thoth Amon does not respect Elbereth.
However, he can be immobilized or taken out from a distance through various means. A wand of cancellation can reliably prevent him from casting spells, as he has very low MR; without them, his weaker melee attacks are easily manageable for a level 14 barbarian. A wand of sleep can render him entirely helpless against the barbarian's powerful melee attacks, and a wand of death can kill him outright.
Men say that he [Thutothmes] has opposed Thoth-Amon, who is
master of all priests of Set, and dwells in Luxor, and that
Thutothmes seeks hidden power [The Heart of Ahriman] to
overthrow the Great One.
A user has suggested improving this page or section as follows:
"More information about fighting, etc. is needed."