User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-95.90.224.203-20171101183240/@comment-1359322-20171103040403

Ise's soul is still that of a human. If the soul breaks then the body dies too. So Ise can't afford to gain anymore rapid power-ups anytime soon. Or he will really die.

Besides he attain strength that average supernatural being can't attain in years. No point rushing too much now, otherwise Ise will just end up as another Saitama.