Fullmetal Alchemist

Through Steampunk

Two brothers, alchemy and automail prosthetics in an industrial, early 20th-century-styled military state. Steampunk-adjacent, and one of the most loved manga ever.

Through Dieselpunk

Two brothers, one in a suit of armour, inside a militarised state modelled on early 20th-century Europe. Alchemy replaces diesel, but the trains, uniforms and state crimes are pure genre.