Boy/man beautiful art love adult

Ever since he discovered the rough sketch for a lost painting by the 19th century French artist Maurice Olivier in a library book, a modern-day art expert, also named Maurice, has yearned to see the actual painting. Is it the work of art he's in love with or its mysterious subject?

He kills people like flies, a schemer and an executioner.
He is also a blade, a chesspiece, an offering to the shrine of power.
Everything ends in the Snow Plains, everything will also begins there.