[Baneslave]

From modding manual:

"7.6.2 #maxage
This maximum age for a monster. After this age it
will risk getting afflictions and eventually die.
Default is 50 for humans, 500 for undead, 1000
for demons. Different magic paths increase
maxage 50% of this value per point of magic,
depending on the type of creature. Inanimate
creatures are affected by Earth magic, undead by
Death magic, demons by Blood magic and all
others by Nature magic."

So human mage with 2 points in nature magic would have max age of 100.