UQ Holder!

Touta Konoe's ordinary life in a rural town is disrupted when Katherine McDowell, a vampire, reveals her true nature and makes him immortal after saving him from a life-threatening injury. This newfound immortality fuels Touta's desire to reach the top of Amanomihashira, a tower that serves as a gateway to outer space. He joins the UQ Holders, a secret organization comprised of immortals, and gains a new circle of allies and mentors, setting the stage for his magical journey.