This challenge is called the Family Challenge, and the purpose of it is to write about the interactions and relationships between relatives. For example, you could write about Thetis and Achilles; Arthur, Igraine, and/or Morgan le Fay; Loki and his children Fenrir, Jormungand, and Hel (and their mother the giantess Angrboda, or even Loki's true wife Sigunn [a goddess of fidelity, amusingly enough])... you get the point. The possibilities are endless!
Remember, any member can issue a challenge, and all challenges are continuous, meaning you can answer any of them at any time regardless of how long ago they were issued. If you would still like to take a whack at the Unconventional Pairings challenge, feel free! And as always, please remember to leave feedback if you read anything that you enjoy or are intrigued by in this community-- it's courteous, and I'm sure the author will appreciate it!