Thetis ( THEEH-tiss, THEH-tiss; ‹See Tfd›Greek: Θέτις [tʰétis]) is a figure from Greek mythology with varying mythological roles. She mainly appears as a sea nymph, a goddess of water, and one of the 50 Nereids, daughters of the ancient sea god Nereus. When described as a Nereid in Classical myths, Thetis was the daughter of Nereus and Doris, and a granddaughter of Tethys with whom she sometimes shares characteristics. Often she seems to lead the Nereids as they attend to her tasks. Sometimes she also is identified with Metis.
https://en.wikipedia.org/wiki/Thetis