"Hey, you dumb broad! Don't give up! Get your act together and bring Lord Van back here!"
She is Van's childhood friend and becomes a friend and support to Hitomi.
Merle is a cat girl with short pink hair and blue eyes. She has black stripes on her face, tail, arms and legs, and a puff of white fur at the end of her tail. She wears a yellow-orange sundress with a black mark resembling a cheetah spot. Around her neck is a pink nail file on a black string.
Merle is mischievous and playful, and enjoys swiping Hitomi's things and playing other tricks. Unafraid to say whatever is on her mind, she can sometimes be outright mean, whether on purpose or without realizing it. She is very affectionate toward and protective of Van, and at first is jealous of Hitomi's growing closeness with Van.
She hates seeing Van go through any kind of suffering or distress, and understands his feelings perhaps better than he does, understanding and accepting his feelings for Hitomi because she wants his happiness, and likely also because she cares for Hitomi as well.
In the anime
"I've always been by your side, Lord Van. I know you better than anyone. You're thinking about her. You love Hitomi, don't you?"
Merle was orphaned as a child and Balgus found and brought her to Fanelia. She grew up alongside Van and learned at an early age that Van was half-Draconian, seeing the shocked reaction of the Fanelians when he spread his wings. Since then, she has served as a best friend and moral support to Van and become very attached to him. She often calls his name, running up to him and hugging him, hanging on his arm, licking his face, and sometimes lying in his lap.
When Fanelia burns to the ground after being attacked by Zaibach, Merle runs away to try and find Van. She is captured and brought to Castelo, where she is reunited with Van and tells him that Fanelia burned to the ground, corroborating Allen's second-hand report of the very same from the Asturian merchants. She faints from exhaustion, partially caused by a poisonous seed embedded in her cheek. While she is ill, Van looks after her, making medicine for her and Hitomi to help alleviate the effects of the poison.
At first, Merle is curious and suspicious of Hitomi, and plays small pranks on her, such as stealing her pendant, unaware that it is Hitomi’s special memento of her grandmother. Even though she teases Hitomi, and acts as if she disdains her, she cares about her safety just as Van does. Just before Hitomi is kidnapped by the Gecko People, she attempts to comfort Hitomi by asking why she is crying and is shooed out of the room. Even though she feels slightly insulted, she goes to tell Van that Hitomi is in trouble.
After Van kills the Dragonslayers, he is stuck in a catatonic state, and Hitomi attempts to save him, both getting trapped within Van's mind. Merle, not wanting either Hitomi or Van to die, saves them by yelling for them, creating a beam of light which Van flies through while holding Hitomi in his arms. Later the same day, Naria and Eriya go after the Crusade. Van gets inside Escaflowne but cannot bring himself to fight. Merle runs in front of Van and tells the twin sisters that to get to Van, they’ll have to go through her. Because Merle is a cat girl like them, and perhaps reminds them of their tragic youth as orphans, Naria and Eriya retreat and return to Folken.
When Van attempts to confess his love to Hitomi and fails, and later when he sees Hitomi and Allen kissing on the bridge, Merle stays with him and comforts him. Afterward, Merle helps out with the rebuilding in Asturia, and the children flock to her, asking for candy and toys. Van remarks that Merle understands their plight, since she was an orphan too. Before Van returns to Gaea, Merle accepts that he loves Hitomi, and tells him that she realized it even before he did. She encourages him to go back and find her. During the final battle, Hitomi comforts Merle, who is worried about Van being in danger yet again.
Merle returns to her homeland of Fanelia with Van to help him rebuild it. In the final scene, she is seen waving goodbye as Hitomi returns to Earth.
In the movie
Merle is first seen watching Van as he invades the Black Dragon Clan ship. When Van and Allen are fighting and Gaddes incapacitates Van with his daggers, Merle shows up, notices that Van has been hurt, and kicks Gaddes in the shin, remarking that she's going to "poison" him for being mean to Van.
Later on, Hitomi bumps into her in the stables on the Abaharaki caravan. Merle tells Hitomi about Van's past, and how Van's home country was laid waste by the Black Dragon Clan. She says that Van has been fighting alone for a long time, even if he is traveling with the Abaharaki, and deep down, he's a nice person. The Mole Man comes to see them and senses the stone Hitomi has been holding in her hand. The girls watch Mole Man make the stone into a pendant, and when he asks Hitomi to pay him, Merle stomps on his hands and tells him not to try and run a business.
Before the battle between the two resurrected Dragon Armors, Van tells Merle he wants to go back to Adom, and she is overjoyed. In the film's conclusion, Merle is seen playing games with the children in Adom.