Bastet

"The writers of old called this creature a Bastet. A monster of nightmare that inhabits the twilight world between the living and the dead."

- Gaius to Merlin

Bastets are creatures of magic that resemble large panthers with bat-like wings. They are said to inhabit the twilight world between the living and the dead.

History
After Freya killed her son in self defense, a sorceress cursed her to transform into a bloodthirsty Bastet every night for the rest of her life. Freya killed many people while under the effects of this curse, including several in Camelot.

Freya tried to flee the city under cover of darkness, but was soon cornered by Arthur and the Knights of Camelot. When her curse took effect she attacked and killed Halig, but was mortally wounded by Arthur in the process.

Freya managed to escape with Merlin's help and reverted to her human form. Unfortunately, her wounds were too grievous for Merlin to heal and she later passed away on the shores of the Lake of Avalon (The Lady of the Lake).

Abilities
Basets are powerful creatures that possess great strength, impressive speed, and razor sharp teeth and claws. Combined, these traits allow them to hunt and kill their prey with deadly accuracy. They are also able to fly (The Lady of the Lake).

Mythology
Bastet (also known as Bast, B'sst, Baast, Ubaste, and Basset) was an Egyptian goddess of the sun. She was also the goddess of pregnancy, childbirth, and protection against evil spirits and contagious diseases.

Bastet was depicted as the daughter of Ra and Isis, the consort of Ptah, and the mother of Maahes. She was primarily worshipped in Lower Egypt as a warrior lioness and protector, and as such was seen as a defender of the king and, by extension, the sun god Ra. Bastet was also one of several deities associated with the Eye of Ra.

Over time, however, Bastet became increasingly associated with the goddess Sekhmet, who shared several similar roles. The two were eventually characterized as separate aspects of the same goddess, with Sekhmet representing the warrior aspect of her personality and Bastet - now commonly depicted as a cat - representing the gentle.