Why is Nikki so weak?

He is basically the same except they go into more detail with his parents being abusive drunks and you see how much the gang bullies him and others in the school. Akemi knows him and she likes him, but only as a friend. He is secretly madly in love with Akemi and he wishes she could be his girlfriend. When he finally gets the courage to ask her out, Akemi tells him that he's a very attractive boy but she just doesn't have sexual feelings for him like that. When he sees her kissing Nagumo, he becomes infuriated. He doesn't understand why Akemi would want Nagumo instead of him because Nagumo is just as much of a nerd as he is. It makes no sense and he becomes despondent. Then the gang of bi-sexual vamps come along and mistreat him just like in the movie. And they humiliate him by using him like a slave, teasing him with lesbian sex shows, but refusing to let him participate. When he tries to relieve himself by pleasuring himself the leader of the clique emasculates him by saying it's no wonder that Akemi doesn't want you. She embarrasses him by laughing at his genitals and then claims that Nagumo is a better man than he'll ever be. His envy and jealousy of Nagumo flares into murderous hatred. He thinks about how much of a b i t c h his mother and these women are, and he thinks about his father calling him a punk who will never be a real man. Then the girls continue on and they destroy the piece of Akemi's bookbag that he held and he grabs it with tears in his eyes and he says, "I wish you you were all dead." And then, the Majin(demons) suddenly appear and kill all of the girls. Just like in the movie they offer him power in exchange for human lives. He goes about like he did and then fights Nagumo as Overfiend, and the battle lasts for a while. Then Nikki escapes and returns disguised in human skin. He attempts to kill Megumi, Kuroko and Amano but they are able to drive him away. He then fights Nagumo again and this time the battle takes them toward a factory.The battle ends similar to the way that it ended in the movie but it took Akemi to distract Nikki. She asked him why he did what he did and told him that she understood that he had anger because of his detestable parents, but she was his friend and just because she didn't want him as a lover doesn't mean that she didn't still love him anyway. Hearing that brought Nikki's human mind back into dominance. It was enough of a distraction to cause Overfiend to fatally injure Nikki. And then Nikki slowly transforms back into his human form. He apologizes to Nagumo and especially to Akemi. Tearing up, he told her that he never meant to hurt her but he couldn't help it. Amano, Megumi and Kuroko realize that this poor pathetic boy was nothing more than a pawn in a Makai scheme. Crying,Akemi then holds Nikki and tells him, "I know it wasn't really your fault. It was what they did to you. I don't hate you." Nikki smiles at her and then he dies in her arms. And that's it. A sad end to a sad life.