Could you calculate Morrowseer's age?
Certainly! Thank you, Anon, for this request!
Morrowseer was at least 35 years old at death, presumably older.
On the Wings of Fire wiki, Morrowseer is listed as at least 20 years old at death. However, this is not cited.
Cross-referencing with the timeline, his earliest appearance, his size, etc., 20 (in dragon years) seems like an accurate minimum estimate. (In the canon timeline, he would have been a minimum of 10 years old when delivering the dragonet prophecy, which is what NightWings consider proper adulthood and old enough to visit the mainland.)
Adding ten years to make up for the childhood age loss, this would make Morrowseer a minimum of 30 years old in human years.
Cross-referencing this with Moonwatcher's calculated age, which is a maximum of 13 years old at his time of death, Morrowseer would have been as young as 17 when Moon was hatched. This does not make sense.
Adding an additional five years to buffer for Moon's increase in age, Morrowseer would be at least 35 years old. This would make him 22 at the youngest when Moon was hatched, which is still a bit of a low number. However, this is a minimum age, and Morrowseer could easily be in his 40s, 50s, or older.
Therefore, Morrowseer is at least 35 years old in human years, but ideally even older than that.
Edited for minor numerical error, not affecting overall results.