The Wandering Spirit.

Cian Edmond is a former military retired, now a professor at a university, he dies run over after refusing the confession of one of his students, when he finally finds peace in his life, when he is embracing death, his consciousness was not dispersed and remained stable, without knowing what was happening soon began to move around the place, bumping into walls that could not see, between those movements absorbs a magic crystal which allows him to regain vision of his surroundings. Cian discovers that he was reincarnated as an elemental spirit.