Lina
Valgarv's object of revenge.
When Valgarv does finally confront Lina, he's disappointed that she's unable to fight him on equal grounds. He wonders how a weak, pathetic human like her could have defeated Garv; Lina doesn't bother telling him the truth. Valgarv likely wouldn't care, so what's the point? His hatred toward Lina is what fuels him for most of his time in the series; he becomes impatient with Armace when he's prevented from killing Lina and will stop at nothing to make sure she's dead. This naturally annoys Lina; the last thing she needs to deal with is a powerful, arrogant mazoku that wants to kill her for something she didn't do.
Eventually, Valgarv becomes more focused on summoning Dark Star than killing Lina. As she begins to learn more about the events that caused him to become so full of hate, she starts to view him more as a victim than as a simple villain. She even begins to question who the real bad guys are and her annoyance is replaced with pity.
Since Valgarv as Dark Star offers Lina and her human friends the opportunity to start a new life on a world without ryuzoku or mazoku, it would appear that he's come to a point where he understands that Lina was not responsible for Garv's death. However, at this point, he's also taken over completely by Dark Star and no longer cares about Garv's demise. He just wants to purify the world and start over.
Once Valgarv/Dark Star is destroyed, Lina and her friends should feel like celebrating but instead, they feel a great sense of loss. Even though Lina understands that destroying Valgarv was a necessity, she feels remorseful about it. When Valgarv is reborn, Lina is relieved to see that he's been offered a chance at starting over in life. Their victory now truly feels like something worth celebrating.