Thanks for the chapter!
LN explains it better. In LN Marquess Deek was desperate to save her son by any means and consumed with jealousy over Raphael and his mother. The man in black was already a Dark Magic user but for some reason Mrs. Deek wanted her son to be able to use Dark Magic. as well so sacrificed the mother to give Raphael ability to use Dark Magic. Spell worked, but Deek was so depressed and tired of living from the chronic illness only his memories transferred to Raphael without overwriting and taking possession of him. Mrs. Deek then had man in black fatally wounded, while laughing, with the excuse that since he controls a dangerous power and isn't trustworthy is better for her to kill him off. When prompted she said she'd keep her promise of returning him to his family that she had kidnapped to force him into compliance as had already put them to death earlier. Enraged man in black managed to touch Raphael allowing him to transfer his spirit over as well before his body died and since then has been whispering about getting revenge while pretending to be part of Raphael. However, whatever MC did broke his bond with Raphael causing him and his Dark Magic power to be exorcised from Raphael. Unknown whether clinging to shadows and using all the Dark Magic formulas in room to stay in land of living, wandering around trying to find a new host to haunt, or was completely exorcised and got the one way express train to Hell.
In any case, now we get to find out who the heroine, Maria, has gotten close and will confess her love to along with whether or not MC is able to live on happily, or gets a bad end. Hopefully the manga doesn't end with that and continues on as the next arc in the LN has a whole bunch of funny situations.