Arabella is an elegant long-haired she-cat with white fur and blue eyes.
RainClan's Beginning, kittypet
Arabella is first shown as a kittypet sitting on the porch of a grand twoleg nest. When Rainstar asks if she knows a place to spend the night, Arabella reveals that she is a kittypet, and tells him s good place to sleep is under the porch. She is gone when RainClan comes back later. She is back the next day and goes with Rainstar under the porch, where Arabella shows a distaste for dirt and prey. Later, Arabella takes Rainstar up onto the roof of the twoleg nest to watch the sun set. Here it is implied that she has romantic feelings for Rainstar. The two later leave the roof and she is not seen again until the next morning.
Arabella came into RainClan's Beginning by a moment of random writing. Good way to start things off, huh?
If it's not obvious, Arabella and Rainstar did have a crush on each other.
Sparrowfeather wants to find a way to work Arabella into RainClan's Beginning later... but can't think of a good way.