I've been trying to remember the title for a light novel I was reading awhile ago. It was about reincarnation in a game style world, the MC has an ability call something like "infinite endurance" or "unlimited stamina", I can't remember the exact name. There was also rapid physical aging because of level increase and at one point the mc receives a title, again not sure of the exact name, it was something along the lines of crimson baby.

Anyway, if anyone can help me with the title I would really appreciate it.

I could be wrong but it sounds a lot like Amamiya Akira's "No Fatigue"

No Fatigue - 24 Jikan Tatakaeru Otoko no Tenseitan (Novel)