The Titans (Hercules and Xena)

They were Imprisoned by Zeus and the gods and godesses of Olympus.

Porphyrion
Porphyrion is portrayed as leader, he draws his power from the earth and appears to be composed of plant roots and dirt (maybe rock), he is humanoid in form. His form is later altered by Hera to appear with horns, empty wings, and one large 'trunk' instead of legs. Porphyrion is the only one of the 4 to actually poses the Cronos Stone and he does so with much vigor. He meets his end when he is dropped into Tartarus by Hercules from the sky.

Crius
Crius was one of the Titans, who favoured humans more. He was restored from stone form by Gabrielle and later killed by his brother Hyperion over a disagreement over humans.

Crius is a wind Titan, he is portrayed as being extremely stupid, and somewhat romantically linked to Mnemosyne. He is dark blue in color, with a light grey underbelly and hands and small horns. In some scenes he is portrayed as having a pot belly, and in others he is in relatively good shape. His form is later altered by Hera, giving him large wings, a VERY loud scream and more wind related abilities, this transformation leaves him, as more of an animal than the others, walking on all fours and speaking in only screams. He is the least reluctant of the group to acceot these new forms, actually going so far as to say in his sleep "no, I dont want to change". He is the first of the group to be thrown into Tartarus.

Mnemosyne
Mnemosyne was one of three Titans chained underneath the world by the Olympians. She was briefly released by Hera Mnemosyne is the sister of Kronos, Helios, Oceanus, Hyperion, Crius, Coeus, Iapetus, Rhea, Tethys, Thea, Phoebe, and Themis.

Tethys
Tethys is a water Titaness, she is shown having a blue body composed of ice, long white hair and webbed hands; she is the most humanoid of the featured titans in her original form. Her form is later altered by Hera to appear to be made completely of water (so that physical attacks do her no harm), have a mermaid like fin that sprouts into octopus tentacles instead of legs and a more purple color as apposed to her original blue. She is shown to be the only one of the Titans to accept her new form right away, smiling after examining her new-found powers. She meets her end when she runs into Mnemosyne, causing them both to fall into Tartarus.