A practitioner of necromancy, often in fantasy or occult contexts. Cross-referenced with ネクロマンサー, which is a common loanword synonym.
See also: ネクロマンサー
In that game, necromancers can control the dead.
A direct loanword from English 'necromancer', often used in similar fantasy contexts. 死霊術師 is the native Japanese equivalent.
Compound of 死霊 (しりょう, 'spirit of the dead') + 術 (じゅつ, 'art, technique') + 師 (し, 'master, practitioner'). The exact historical derivation is uncertain, but the term follows a common pattern for naming practitioners of a magical art.