mephistophelean vs mephistophelian

mephistophelean and mephistophelian both are adjectives.

Word	Noun	Adjective	Verb	Adverb
mephistophelean	No	Yes	No	No
mephistophelian	No	Yes	No	No

As adjectives, mephistophelean and mephistophelian are synonyms defined as:

mephistophelean and mephistophelian: showing the cunning or ingenuity or wickedness typical of a devil

Other synonyms of mephistophelean include devilish, diabolic, diabolical.

mephistophelean (adjective)	mephistophelian (adjective)
showing the cunning or ingenuity or wickedness typical of a devil	showing the cunning or ingenuity or wickedness typical of a devil