Seth
He is often depicted as a man with the head of a mysterious animal; sometimes interpreted as anteater.
Seth is the son of Nut and the brother of Osiris, Isis and Nephthys.
It is said that Seth murdered his brother Osiris, causing a long, violent fight with his nephew Horus over who should be the earthly ruler.
Finally other gods were called to judge and they decided that Horus should rule over the living.
Lara freed Seth, when she visits his tomb in The Last Revelation.
He is also the boss and Lara has to fight him in the level Temple of Horus.
He mysteriously appeared in the temple, probably travelling in non-corporeal, accompanied by a swarm of locusts - as said in the prophecy - before assuming his God form as shown in the image. He is invincible, and Lara escaped the temple by dodging his attacks which consisted of energy missiles and beams. Once Lara climbed out of the temple, she used the Amulet of Horus to close a trap door and seal Seth within the temple for all time.
Seth destroyed the Armour of Horus, to stop Horus from being summoned by Lara who assembled the armour. The armour was destroyed but the Amulet of Horus was knocked into the surrounding water and retrieved by Lara.
Seth can be playable in the Tomb Raider Level Editor.