Arke (or Arce) was a daughter of Thaumas and Elektra, fraternal twin sister of Iris and older sister to the Harpies . Arke is sometimes affiliated with the faded second rainbow.
Arke, during the Titanomachy (Titan Wars), decided to become Messenger to the Titan Gods, whereas her sister Iris, became Messenger to the Olympian Gods. After the Titans were defeated by the Olympians, Arke was stripped of her iridescent wings by Zeus who also imprisoned her and the vanquished Titans in Tartarus. The Titans would be released many years later. Arke's wings were given as a present to the couple, Thetis and Peleus on their wedding day. Thetis later gave them to her son, Achilles, which is said to be where Achille's surname, Podarces (meaning: swift footed) originated.
Thaumas and Elektra