Ah, I found that Youth spell in RMCI. Thanks.
But I also made up a complete spell list. Of course, I have no idea if the spells are balanced well enough or not, and still don't know what the approriate realm could be. I am open to suggestions.
Age Mastery
1 Know Age - Tells the caster the exact biological age of the subject.
(An elf or member of another immortal species will register as 25 years.)
2 Ease Ailment I - temporarily removes one age-induced ailment from the
subject for 1 day. Such ailments include pain in the back, loss of fertility, diminished sight,
failure to hold one's urine, even alzheimer's disease, if and only if their
cause is age. This spell, however, does not affect your appeareance in any way.
3 Beauty of Youth I - temporarily lets your appearance return to its former beauty,
removing up to 1 year per level from your appearant age. This spell does not affect
any age-related health effects, it merely adjusts the subject's visible age.
4 Tell Remaining Years- Tells the caster the subjects's remaining years, excluding
any "external factors" like violence or plagues.
5 Beauty of Youth II - as Beauty of outh I, but changes your visible age by up to 3 years per level.
6 Ease Ailment III - as Ease Ailment I, but the product of the number of
ailments and the number of days the ease lasts is 3.
7 Wisdom of the Years - Temporarily improves the subject's self dicipline bonus by +1 per level.
8 Mass Ease Ailments I - as "Ease Ailment I", but affects a number of targets equal to the caster's level.
9 Ease Ailment V - as Ease Ailment I, but the product of the number of
ailments and the number of days the ease lasts is 5.
10 Temporary Youth - temporarily reduces the subject's biological age by 1 year per level. (Duration: 1 Day).
This spell does not remove any skills, injuries, lost limbs etc.
11 Respect for the Elders - temporarily increases the subject's self discipline, charisma, and empathy bonuses by +1 per level.
12 Beauty of Youth V - as Beauty of youth I, but changes your visible age by up to 5 years per level.
13 Mass Ease Ailments 3 - as "Ease Ailment 3", but affects a number of targets equal to the caster's
level, with the factor of 3 applying to each subject individually.
14 Ease Ailments X - as Ease Ailment I, but the product of the number of
ailments and the number of days the ease lasts is 10.
15 Lesser Halt Aging - Halt aging of the subject for 1 year.
20 Greater Ease Ailments - as "Ease Ailment I", but cures all age-induced ailments of the subject permanently.
However, the subject will quickly aquire them again from natural causes if its biological age isn't changed.
25 Greater Halt Aging - Halt aging of the subject for 10 years.
30 Youth (as the Level 50 spell from RMCI)
50 Permanent Halt Aging - Permanent, hereditary halting of subject's aging (if inherited, aging stops at biological
age 25 - this only works if both parents are immortal by this way or another)