numbered according to pharagraph:
1. From beginning it was clear he wanted his father's power. During their first fight til the last with Dante. And yes he used Arkham, but that's a evil person, i doubt he would use a human with pure heart and cast this person aside when he is finished with using her/him.
Evil or good don't matter to Vergil. If the person with a pure heart was not useful to him, Vergil would leave them, put them in danger out of neglect or outright kill them.
I don't like Arkham either, but regardless, Vergil attacked him without warning. Arkham thought Vergil was his ally. He did not expect Vergil to stab him.
3. Well they are brothers, twin brothers, and they share the same blood. Plus before Dante awakened his demonic form, he was stabbed (in opening) in chest, arm and legs.
Dante was stabbed during the attack at his shop. But Vergil did not see this. I wager that Vergil sent Arkham to confirm Dante had the amulet, then sent the demons to get it, not caring that Dante might not have his powers and would be injured or dead as a result. All Vergil cared about was the amulet.
4. I find it very odd to fight a demon just to prove your superiority. And why would Vergil care for a single amulet without having the other? The amulet were given to him by his mother, so if he cares about his mother, he could care about a girl that has been kind to him. And like i said, him using a evil person and possibility of using someone with pure heart...sounds very questionable.
[/quote]
But Vergil did fight demons to prove himself worthy of being the son of Sparda. He fought Beowulf to prove himself and because Beowulf bad mouthed Sparda. Vergils also says at the encounter with Mundus that if his father could fight Mundus and win, then he could also do it too. Vergil is all about trying to gain power to be like Sparda and embrace his demonic bloodline.
He cares about the amulets not because of the sentimental value of being a gift from his mother, but because the amulets, once combined, open up the gate to hell where Vergil thinks he will claim Sparda's power. There's no evidence to say he cared about his mother at this point in the game. Even if he did, would caring for a mother also translate to being able to care for some random girl who once showed him kindness? I doubt it. Vergil only cares for people who are useful. If the girl was no longer useful, he would not care for her. If Vergil can hurt, stab and manipulate his own brother, then I doubt he would be caring to humans who do not have the blood of Sparda.
Also, why do you cling to this idea of a girl who helped him, or person with a pure heart? Being a good person or pure would not matter to Vergil. All he cares about is using a person and then discarding them. If he can betray his brother, his own blood, then I hold no hope for Vergil forming any meaningful attachment with a human, pure heart or not.