The troublesome thing about the Vampires is that they cannot be evaded. The Vampires can sense all of them and will always find them. The only one who is safe from them is Helios.
It is not because of a weakness for sunlight. They avoid Helios because he will burn anything up regardless of its weakness to light. The other clones are busy, so they have to let Ragnarok suffer from their abuse.
The alternative is to fight the Vampires, which they can do and have done, but they can't kill them permanently because they have true immortality now too. It is another one of their upgrades, apart from the lack of weakness to light. This is thanks to the evolution of CARNAGE.
Ragnarok has an armored body of Liquid graviton, and he heals better through devouring than all of them, so he became the designated sandbag. That's how he has been able to withstand attacks from several Vampires.
