Stronger word for "selfish"

Synonyms like "egoistic", "egocentric", "self-centered" "self-loving", etc, are no stronger than selfish. I would use an adverb before "selfish" lest its exact meaning be changed. "Egocentric" and "self-centered" are not exactly the same as selfish.

He is extremely/incredibly/profoundly/exceptionally/monstrously/etc selfish.

Egomaniacal:

• overly concerned with one's own desires, needs, or interests

  • a brilliant but egomaniacal urban planner who ruthlessly sought to impose his vision of the ideal cityscape (M-W)

Avaricious denotes a kind of selfishness that knows no limits.

From the link:

avaricious | adjective | av·a·ri·cious | \ˌa-və-ˈri-shəs\

• greedy of gain; excessively acquisitive especially in seeking to hoard riches

an avaricious scheme to con the elderly couple out of thousands of dollars

Exploitative.

One wants his/her own profit at others' cost. He/she does not care about others.