Books in the The Unwanted Undead Adventurer (Manga) series

It¿s been ten years since Rentt Faina, a luckless Bronze-class adventurer, set his eyes on becoming Mithril-class. Unfortunately, he finds himself helpless when confronted by a legendary dragon in the Water Moon Dungeon...and is summarily eaten. But Rentt has miraculously reawakened...as a skeleton?!Making his way back to civilization is going to be a challenge when he can barely walk, let alone hold a sword. And the good people of Maalt won¿t take kindly to a monster in their midst. Can some magic techniques and a chance encounter provide Rentt¿s salvation?