Unknown to exist until the Annadil Crisis, Hiko spent most of the last forty years in Arden, which she was known to love (in a rather literal sense, given that she was the Green Knight's Lover). She had become somewhat reclusive, although those who visited her found her a gracious and quite sociable hostess.
Hiko was bound in service to House Alars along with her child when Morgan managed to get them both captured, after her previous actions resulted in the destruction of much the House and the deaths of many of its members. She survived to serve them only a short time, annihilating herself at the final battle against Hel's Chaosians after she poured her life force into a massively destructive spell that slew the Wu of Lady Suroth, the killer of her child, and wreaked much havoc upon both sides of the battle.
An Embran version of Hiko appeared in a shared dream triggered by the Wings of the Dragon recently.