Like his brother, Gilles, I looked for Frankish names that I could derive a more modern French name from.
Isaac's true name is Helisachar.
Looks 35 (Is really around 1470~)
This doll's character is available for offsite roleplay.
One of Lyon's biological children, Helisachar was not particularly strong or impressive. He probably wasn't even one of the smartest of Lyon's living children at the time. But he did know how to game people.
And that eventually included his father, who he tricked into turning him into a Dragon.