Svengali

[ sven-gah-lee, sfen- ]

/ svɛnˈgɑ li, sfɛn- /

a person who completely dominates another, usually with selfish or sinister motives.

Origin of Svengali

First recorded in 1940–45; after the evil hypnotist of the same name in the novel Trilby (1894) by George Du Maurier

But one look at the film is enough to dispel all notions of Svengali.

The Legend With The Look: Remembering Lauren Bacall |Teo Bugbee |August 13, 2014 |DAILY BEAST
Well, he was no Svengali, no alchemist and, obviously, they would have happened without him.

What It Was Like to Watch the Beatles Become the Beatles—Nik Cohn Remembers |Nik Cohn |February 9, 2014 |DAILY BEAST
One wondered if she were not paying out Svengali for his impertinent performance of "Messieurs les tudiants."

Trilby |George Du Maurier
His touch on either canvas or paper was like Svengali's on the key-board—unique.

Trilby |George Du Maurier

Gecko with a knife, and people holding him, and Svengali bleeding on the ground.

Trilby |George Du Maurier
That terrible figure of Svengali still sat, immovable, watching his wife's retreat—still smiling his ghastly smile.

Trilby |George Du Maurier
At table d'hte not a few of Svengali's opinion, that "only the dirty want to wash."

Punch or the London Charivari, Vol. 109, September 28, 1895 |Various

Svengali

/ (svɛnˈɡɑːlɪ) /

a person who controls another's mind, usually with sinister intentions

after a character in George Du Maurier's novel Trilby (1894)