Timeless Body

Extensive use of the well of souls inherently slows aging. Remove Timeless Body from all class lists. Then, any class that can cast spells adds this new version of Timeless Body to their class at whichever level they become able to cast third level spells.

Timeless Body

Your connection to the Well of Souls has slowed your aging. For every two years that passes, your body ages only 1 year. If you gain the ability to cast sixth level spells, it becomes every three years instead. If you gain the ability to cast ninth level spells, it becomes every four years instead.