Source : Webster's Revised Unabridged Dictionary (1913)

Necromantic \Nec`ro*man"tic\, Necromantical \Nec`ro*man"tic*al\,
   a.
   Of or pertaining to necromancy; performed by necromancy. --
   {Nec`ro*man"tic*al*ly}, adv.

Source : WordNet®

necromantical
     adj : relating to or associated with necromancy; "mysterious
           necromantic rites" [syn: {necromantic}]