|Information in this article is non-canon|
He is the son of Littlefoot and Ali, the brother of Ariana II, the grandson of Littlefoot's Mother, Bron, and Ali's Mother, the great-grandson of Grandma and Grandpa Longneck, and the great-great nephew of The Old One.
He in most ways resembles his father though he has the same eye color as his mother. He is mischievous and he, along with his sister Ariana II, were once reprimanded by their parents for pretending to be Egg Stealers and actually stealing eggs from nests.
Thunderfoot likes Tree Stars and berries the most. He often gets into fights with his sister Arianna II. Indeed, Littlefoot, on a few occasions, has gotten so annoyed with him and Arianna that he has joked that he'd feed them to Chomper, though, admittedly, Chomper has no intention of eating them, but sometimes plays along to scare the kids.
In one memorable incident, when Thunderfoot tried to cross the Sinking Sands without permission, Littlefoot referred to him as "Ali's son", causing Ali to tail whack him in the head.