Van and Merle were both orphaned at a young age and were taken care of by Balgus. When they were children, Merle witnessed Van spreading his wings on a dare, and saw and heard the shock of the Fanelians. Wanting to protect Van from the disdain of the people, she encourages him to withhold his wings unless absolutely necessary, such as when he needed to save Hitomi from falling.
After Fanelia is destroyed and Merle is left behind, she runs off to look for Van. When she is taken prisoner, she is reunited with Van, and Van says he is glad she was able to make it out alive. She comes down with a fever due to the effects of the poisonous seed Van finds embedded in her cheek. He asks the Mole Man for help to make medicine to cure her and Hitomi.
When he talks to Hitomi about her family, Van acknowledges that Merle is like family to him. They have known each other all their lives, and since they are the only two remaining from Fanelia, at least for quite a while, that they know of, they share the mutual burden of knowing their country was destroyed. Although he does not outwardly show affection for Merle in the way she does for him, she still means a lot to him. When he is trapped inside his own mind after murdering the Dragonslayers, it is Merle’s voice that causes him to awake from his catatonic state.
Merle is very attached to Van and is always hugging or clinging to him. She hates to see Van in any kind of danger, and sometimes she even protects him, such as when she stopped Eriya and Naria from attacking him while he was struggling with his fear of fighting. Even though she realizes that Van does not return her own crush on him, Merle is jealous of Hitomi for a while. However, she acknowledges that Van is in love with Hitomi, and sees how important she is to him. When Hitomi returns to Earth for the first time, Merle tells Van she understood his feelings before he did, encouraging him to go back and find her.