A character in the anime series Tenkuu no Escaflowne (or Vision of Escaflowne). Pronounced "Meruru" or "Merulu" by the Japanese cast ("Merle" is just too hard for native-Japanese speakers to pronounce properly), and often spelled that way by fans. Merle (Meruru/Merulu/Meryl) is a catgirl, one of several to appear in the series. She's about thirteen years old, (a couple of years younger than the main characters) and (not surprising for a young teenage catgirl) very cute. However, she can be annoying too, especially to those who don't care for cats. More even than many other catgirls, Merle acts like a cat. I love cats though, and thus Merle's antics don't bother me at all. Merle is also more catlike in appearance than is typical for anime catgirls, having apparently a full coat of fur, in addition to the cat ears and tail. The (very short) dress she wears has a pattern reminiscent of leopard spots.
The youngest of the catgirl characters, Merle serves as a sort of kid sister to the other characters (although her attraction to Van Fanel sure seems more than sisterly, but she's still young). She is often seen glomping Van, and screaming Van-sama! in a really piercing voice. This can be very annoying, but for my part, I really wish I could have a cute catgirl to cuddle up with, obnoxious voice or no.
What's more, Merle is actually useful from time to time in the series. Despite being the rival of Hitomi for Van's attention, she helps him rescue Hitomi when she gets kidnapped early in the series. Also, the Lesbian Catgirl Sisters, Eriya and Naria, have a thing against harming other cat-people, and won't attack if there's a danger of harming Merle.
While Merle's speaking voice can be annoying, her singing voice can be described simply as "adorable." Her voice actress sings the song "Neko no Kimochi" on the Escaflowne soundtrack CD called "Lovers Only." This has got to be the cutest song ever made. It's the song that a cat would sing. Whenever I hear it, it makes me wish I had a little kittycat curled up and purring on my lap. Aw, there I go again, turning into undifferentiated mush at the very thought.
In general, I'd say that Merle is probably my favorite character in Escaflowne. Sure, she doesn't have any mystical powers, doesn't operate a giant robot, and can't fight, but she's cute and, hey, she's a catgirl!