How does Chris/Auri/Erich's vampirism compare with Ryan/Corrine?
Two entirely different takes on vampirism.
The Adze (Corinne and Ryan - or well half of him) can shapeshift into a firefly, although Ryan didn't actually know that yet during the Bad Arc, although they are stuck in human form when trapped anyway. They have the power to possess humans, and often negatively affect the lives of the people around them. They are known for feeding on children or while people sleep, making their way through closed and locked doors. They are not subject to the rules about who can enter a house.
Other aspects that came from my story:
They can choose to have fangs or not in appearance.
They are not particularly social - that part of Ryan comes from his father. Ryan is born half-vampire, but can also make vampires in a kind of consummation where he feeds and is fed from at the same time. There isn't venom, but being fed from is pleasurable.
Auri/Erich/Chris have a few rules - silver hurts them or weakens them, although no other metal does. They must be invited into a home that anyone who is alive is residing in, and if they leave it for three days or longer, they have to be invited again. They have fangs all the time. They do not have heartbeats, they do not breathe. They are trapped physically in time of their death - so if Auri cuts their hair, for instance, it will be back to the same length after they sleep. Chris will always appear sixteen/seventeen years old.
They feed significantly more often than Ryan's type of vampire. Thirst will drive them mad eventually. They tend to group into small packs with a 'packleader' and the people the packleader has turned, the people they turn, etc. Except that Turning people is actually fairly rare because once you do that, you're responsible for them. To become a vampire, you must be drained near to death and then fed the vampire's own blood.
Vampire venom numbs the victim and is a kind of strong sedative, distilled and used in medicine and also as a recreational drug. It is strongly physically addictive.
When vampires push venom into each other, though, it's an intense overwhelming physical pleasure and brings on euphoria.