The Gwythaints are the Horned King's personal aerial scouts in the Black Cauldron. They are also called the Wyvern twins in the spongebob adventures universe. One of the gwythaints fell to its doom, while the other is currently still at large alongside the Creeper. the one that fell is rumored to somehow avoided banishment and eventally caught up with the other and Creeper. it's confermed that the wyvern twins are female, as mentioned by Devon and Cornwall. also mentioned by them that their names are Rebecca and Surly, although they're not sure which is which.