We know why the ancient Egyptian goddess Neith was part of that team of four goddesses-mourners (Isis, Nephtys, Neith and Serket) protecting the dead.
Serket was also a very important divinity in the Egyptian pantheon. She had a great healing power and for that reason she was invoked in ancient Egyptian remedies against scorpion bites.
In the funerary sphere of Ancient Egypt Serket helps the Egyptian solar god in his daily rebirth. Re, during his journey in the darkness of the night has to fight against his enemy, the serpent Apophis, which is facing the solar bark.