The Tomb of Oracleus [1]

Cra Crack—!

A cracking sound echoed through the air as I sat motionless with my eyes closed. My muscles shifted, and my bones ground against each other.

"Hoo… Hoo…"

I kept my thoughts steady as my chest heaved up and down repeatedly. I could feel changes occur to my body as I remained composed and let the cool energy within my mana core run around my entire body.

While there were differences between each Tier, the real changes occurred once someone entered Tier 4. That's when a true gap would appear. For each subsequent Tier after that, a new change would occur with the creation of a Domain in Tier 5 being the biggest example.

In the case of Tier 4, one would undergo Body Reformation.

It was a process in which the body adjusted to the sudden increase in mana intake by fortifying the bones and muscles.

The process was decently painful, but that was about it.