[Taqwus]

All units have an age threshold over which they are considered 'old'; for ordinary humans, this tends to be 50.

They also start with an age based on this threshold, how much magic they have (the more, the older), and a shift based on the unit type.

Units which are old suffer some stat penalties. They also have a chance to gain afflictions as they continue to age; if they get the 'disease' affliction, well... 1hp/month of aging.

There is only one spell which lowers a commander's age in the unmodded game; namely, the blood spell Rejuvenation which lowers the age of the caster.

You can -stop- a unit's aging with Boots of Youth (again, blood magic) or with an Elixir of Life (nature and fire).

Gift of Health will not stop aging, but it halves the rate; I think the healing effect (as well as that of the Chalice) should also cure the afflictions accrued.


== Edit: additions below ==

Mmm yes, commander's magic matters along with scales. A growth scale reduces the affliction chance, while a death scale increases it. A caster with death magic also has a reduced affliction chance, if memory serves. Nature magic increases the old age threshold while fire magic lowers it.