Megami "Isekai Tensei Nani ni Naritai Desuka" Ore "Yuusha no Rokkotsu de"

The protagonist of the tale, simply referred to as "I," experiences an endless cycle of reincarnation. The narrative takes place in a different universe where people are free to select their next form. However, the waiting list for popular roles, like "Demon King" or "Hero with Cheat Skills and a Harem," has reached 50,000 years due to a recent spike in applications.
The protagonist decides to repeatedly reincarnate into increasingly strange forms because he refuses to wait. These roles include the rib of a hero in charge of a harem, a hermit crab, a vegetable, and even an explosive used to blow up blissfully happy couples.