Eccarius was no doubt a longtime fan of Anne Rice before he was turned. He embraced his new role as a Child of the Dark. He wore frilled shirts and capes, lived in a Gothic mansion and drank blood from crystal goblets. He spoke at length about their "dark curse" and "exquisite torment." He slept in a coffin.
He was, as fellow vampire Cassidy put it, a wanker.
In addition to his own affectations, Eccarius encouraged them in others. There was a group of disaffected youths in New Orleans who idolized Eccarius, who wanted to become like him. They called themselves, unsurprisingly, Les Enfents du Sang.
Les Enfents were the worst kind of vampire-worshippers. They met in a basement with arcane symbols painted in deep red on the walls. They wore black clothes and too much eye makeup. They wrote bad free-verse poetry about Eccarius. They even cut themselves and drank each other's blood. What was worse, Eccarius encouraged that kind of idol-worship.
Cassidy dragged Eccarius out by his ear, but not before breaking the jaw of Mako, the toughest of the group. From there, Cassidy set about Eccarius' re-education.
They spent several days around New Orleans, where Cassidy taught Eccarius that beer was better than blood, that they had nothing to fear from churches, and that nearly everything Eccarius thought he knew about being a vampire was wrong. In the end, they went back to Les Enfents' lair and mooned them. Because it would be funny.
In the end, Eccarius' ego won out over his reason. Cassidy found him draining the blood of one of the younger members of Les Enfants du Sang on the altar of a church. He loved the idea of being a vampire more than the reality of it, and loved having a group of devoted followers that he could feed from. He admitted that he'd killed before, for no more reason than he enjoyed it.
Cassidy knocked him unconscious and then nailed him to the roof of the church, where Eccarius exploded in the morning sun.