Tsuihou Sareta Tensei Juukishi wa Game Sashiki de Musou Suru

From Seven Seas:
Nobody in this world wants to end up assigned a class like “Heavy Knight.” Nobody, that is, except for Elymas Edvaughn, who knows from his memories of a past life that the class is an absolute monster for those who know how to use it. But the path of the Heavy Knight is particularly difficult in a society that doesn’t know the true strength of the class! Exiled from his family, Elymas sets out to game the system and show the world his true power!