I'm working on a comic book for an art exhibit this coming spring, and I need a little help/opinion for the plot. They story is malexmale, and set in a 'steampunk' universe. I still don't have all the names/details worked out, obviously:

Ten years before the start of the comic, there was a war between humans and vampires: Vampires though themselves to be superior and tried to rebel against the humans, who coexisted but regarded the vampires with a discriminatory fear.
Not only were the humans at war with the vampires, but the vampires were at war amongst themselves.
One side supported Azel, the vampire supremacist, and the other supported Gabriel, an equalist.
Azel fell, and Gabriel became the 'emperor' or the vampire realm, and the war ended in a truce in which the vampires were subjugated by humans.

Ten years later, the fragile peace has been shattered when the remnants of Azel's supporters began to invade the human realm and sacrifice humans in order to resurrect their fallen lord.
Emperor Gabriel and his teenage son, Kazuma, are called into he human realm to negotiate a fragile peace and deal with the rebels. Here they meet Lilith, a mechanic, Father Kain, priest and a former vampire slayer/fallen war-hero, and the war-orphan Hillell, who has been raised by Kain and Lilith.

Hillell and Kazuma are immediately fascinated by each other in a boyish way, but Hillell seems interested in more.
Kazuma is confronted by Azel's followers, and convinced slowly that his father's weak ways are wrong, and will lead to the downfall and extinction of the vampire race.
Hillell watches his friend slowly falling from grace, and tries to intervene, but on the night that Kazuma runs to go help the rebels, who have taken over the empire in his father's absence, Hillell and Kazuma get into a fight, and Kazuma accidentally shoots Hillell with a silver bullet that was meant for his father.
Realizing what he has done, Kazuma immediately regrets his actions, but is too proud and angry at his father to return.
Upon his dying lips, Hillell confesses his love for the other boy, who returns the favor with a simple kiss, drinking his friends blood.
At the last minute, Lillith, who has taken on Kain's former role, intervenes, and saves Hillell, but Kazuma gets away.
Hillell begins the painful transformation into becoming a vampire, and over the next five years (timeskip) becomes a man who not only slays vampires, but humans who do wrong as well.
Azel is re-encarnated, and now the humans and vamires are at war again, but when Hillell come face to face with Azels' 'right hand', Kazuma, neither man can bring himself to kill the other.

(side drama with Lilith and Kain not included, but I'm toying with their roles in the series. One thought I had is that they are secretly Hillell's parents, but because Kain is a priest, it had to be kept a secret. It would certainly make it canon for Lilith to be hanging around the cathedral a lot)

Okay, a couple things. When talking about reincarnation, it's been my experience that there should be differences. For example Azel, should have less power than before or have to inhabit a different body(which is actually Kazuma) or something along those lines.

Another thing is I like the idea of drama with Kain and Lilith however the subplot you mentioned is incredibly cliche. I would keep Hillell an orphan, because the mystery of his parents adds to the story. I also find it pretty cliche that a priest would have a secret child. Instead I think I'd make Lilith and Kain siblings of some sort, and maybe Lilith has another identity no one knows about or something(forcing her to lie to her priest brother).

Anyway, these are just ideas. Try to stay away from cliche plot lines though, they kind of make a story dull or cheesy.