Xyon

Xyon was a half-Vulcan, half-Hermat hybrid born to USS Excalibur (NCC-26517-A) officers Burgoyne 172 and Selar in the year 2376.

Xyon's unique hybrid nature caused him to age and mature rapidly. His mother, Selar, spent most of her off-duty hours trying to find a way to reverse Xyon's rapid aging.

By 2379, the barely three-year old Xyon was fully mature and educated, and even served as science officer onboard the Excalibur.

It is currently unknown if Selar was ever able to stop Xyon's rapid aging. (NF novels, Dark Allies, After The Fall Missing In Action )