Talk:Shizu/@comment-26320293-20190622150706/@comment-10330822-20190622224509

You're right, it doesn't make her immortal, just younger appearing. She stilll was like 75+ years old or close to it.

Ifrit is attached to her life force, so it makes her age slower while in her, but damages and kills her if removed.

If you are an anime-only watcher, this may have slipped by you. Spirits, especially high-level ones like Ifrit, are excellent to stablize the chaotic magicules that appear when a World Traveler is summoned. Once it is stablized, the being becomes much longer-living, because magicules fuel life force and power.

Being like Leon and Yuuki were able to stablize their magicules through will and special abilities, but others have required spirits to keep them alive. If you remove the spirit it will kill them, this is true for those children Rimuru helped as well as Shizue.