It can truly be said: Men are the devils of the earth, and the animals are the tormented souls.

[Man möchte wahrlich sagen: die Menschen sind die Teufel der Erde und die Tiere die geplagten Seelen]

Arthur Schopenhauer (1788-1860) German philosopher

Parerga and Paralipomena, Vol. 2, ch. 15 “On Religion [Ueber Religion], § 179 “The Christian System [Über das Christenthum]” (1851) [tr. Hollingdale (1970)]
    (Source)

(Source (German)). Alternate translation:

One might say with truth, Mankind are the devils of the earth, and the animals the souls they torment.
[tr. Saunders (1890)]