I drew baby Myia again, since I wanted to explain how the Heradries age.
This is talking about the OG 24 siblings.
Each one was thought into existence, there's is a certain name for this theory and I don't remember what it is. Anyways, the first year of the baby goes quickly, by the time they're 6 months old they're the equivalent of a human sixteen year old and they turn 17 by age 75-ish.
For example, (the alive youngest) Pers is about 1876 yrs old but she is the equivalent of a nineteen year old (but honestly she is more like an old lady from the 20s).
Myia (the middle child) is 3755 yrs old and is the equivalent of a 25 year old (For him I think of him as a 1960s lowrider guy, think The Cramps)
Ann and Alastor (They are one being that split in two) (the eldest) is about 176 500 yrs old and is regarded as a 29 yr old (I think of Ann as a academic victorian woman (and or book hoarder) and Alastor as a recluse geologist from Cornwall
Think of it as a exponential graph going up until it looks like a straight line (but it really isn't a straight line, there's a teeny tiny curve). So maybe the siblings are never going to get old, I dunno, they can die from anything else, though.