It seems kinda obvious since Ouyang is connected and possibly in charge of the experiments. Since Luo Fan was used as an experiment and then possessed by Satan, it's safe to assume that Ouyang is connected to Satan in some shape or form. If Mo Yuxun is connected to Ouyang, then he is also indirectly connected to Satan. I feel like in the end either Saran of Ouyang are cooperating as equals or Ouyang will end up being the final boss rather than Satan

Hostage?

Remember that deranged pharmacist kid. You know the one who fought with shen yanxiao because he kicked out tang nazhi. He came from another kingdom.... his name was lou.. I think.... lou fan? I'm really not sure. Let's say he is called Lou fan... Remember lou fans master was a famous pharmacist but he was actually secretly someone from ouyang huangs team. That's when we found out that lou fan had a suitable body. We assumed for experiments. However at the beast tide remember that lou fan appeared. Satan used his body with distaste but it was the only available one that was 'sutible' enough. That's when we found/assumed that Ouyang and those warlocks are connected with Satan. Obviously that kids (the experimental bodies) master is Ouyang so he obviously has connections with Satan aswell. I hope that explained. You probabaly forgot since there's been a lot of filler chapters 😀

Just a little correction: When the beast tide hit Rising Sun City, Ouyang Huanyu was there with Luo Fan's master, "watching the show". They're talking about some sort of deal with Satan. So, OH and Satan's cooperation was not even a speculation. It's confirmed. But, how far and what the details of their cooperation were, we haven't known further.

Bunjin