Shinketsu no Kyuuseishu ~0.00000001% wo Hikiate Saikyou e~

A player who can fight creatures from the wonders of another world. The main protagonist, Ariake Subaru, was bullied and was chosen as a player of the "Rainbow" rank, which is neither gold, silver, nor copper. He acquired the skill to freely manipulate blood, and his life and position changed completely. As he continues to fight every day, he gradually earns the title as a "Savior" who will save the world.