Kapitel 980: The Plan For Ragnarok: Dark Side.

The demon god answered Xigger's question. "I was worried about you so I told some Vampires to follow you for protection."

Asking other vampires to go and reinforce Xigger and keep him safe is certainly not acting against Ragnarok indirectly or directly. After all, the demon god has the right to order its Vampires to do its bidding as long as it doesn't send them after Ragnarok. 

The demon god is just protecting its asset. It is allowed to do that. The fact that Xigger will be close to Ragnarok and therefore make the other vampires close to Ragnarok is but a coincidence. 

It will also be a mere coincidence that has nothing to do with the demon god if one of those vampires takes a fancy and decides to turn Ragnarok without being prodded or influenced by the demon god.