Quor'toth had lain in slumber in its own dimension for at least several millenia.
When Connor entered Quor'toth for the second time, his loving and merciful nature that he inspired in his followers awoke Quor'toth. Quortoth lumbered its way over to Team Angel and fired its beam attack on them. Willow tried to protect them with a forcefield, but Quor'toth's power was too much. The hate and negativity of the dimension caused her to go Dark and the two engaged in a magical duel.
It ended when Willow lifted a mountain top and throw it on Quor'toth which allowed them to get away. However, the assault only slowed the Old Ones done who recovered moments later, prompting the team to leave.
Powers and abilities
Quor'toth had a gargantuan size and had proportionate strength. It was able to influence people who inhabited its dimension. It also possessed a powerful breath attack. His level of power directly rivaled that of a fully magically charged Dark Willow.