Nereids

In Greek mythology, the Nereids (also known as sea nymphs) are fifty daughters of Nereus and Doris (sisters of Nerites). Their cousins are similar to the sirens and they accompany Poseidon. They are patrons of fisherman and sailors. The nereids can be very helpful to sailors in distress, also helping them fighting against storms at sea.

Mythology
The nereids are associated in the Aegean Sea where they dealt with their father in a silvery cave. The most notable of these nymphs are Thetis, Amphitrite (wife of Poseidon), and Galatea (lover of the cyclops Polyphemus).

In the Iliad XVIII by Homer, when Thetis cries out in a grief of Achilles for killing Patroclus, her sisters have appeared. Another nereid (Opus) is mentioned the Aeneid by Virgil. She is called on by Diana(the goddess of the hunt and moon) to avenge the death on the warrior Camilla. Opis gets weapons to take revenge on Camilla's killer, the Etruscan Arruns. Opis has lamented Camilla's death and later shoots Arruns as directed by Diana.