TW FOR SPIRALS, BOUNDARY PUSHING, MANIPULATION, MEMORY LOSS, FUSION??, CLOSE PHYSICAL PROXIMITY, IMPLIED ABUSE (AGAINST WILLOW), VENETICUS HAS POWER OVER BASICALLY EVERYONE AS THE HOST OF DESOLATUS—SO THATS WHY HE HAS SUCH CONTROL OVER EVERYONE, DEATH, GRIEF, PARASITE METAPHORS, BLOOD IMAGERY, STABBING, ETC.
So, I think they'd have a rough start from the beginning? Michael would somehow end up on the Isle of Desolatus, out of curiosity most likely—and wanting to see who the new 'Host' is, where he winds up meeting Veneticus. Hes chill with Vene, and seems to be intent on leaving the second he sees the new host since he is aware of the dangers of the Isle. But—Veneticus is very fascinated by him, who he is, and where he came from—especially since he appeared through a random door. So he bombards him with questions, wont stop following him around, and will not stop getting close to him—and also does as he does with anyone who enters the Island, which is try to break their boundaries of purpose until they stop trying to fight back against him. Despite this, Michael at some point stabs him, but Veneticus is determined to keep him until hes satisfied. So Michael is forced to stay for a few weeks, and months—continously trying to escape. Veneticus occasionally lets people in so Michael can eat, since he learns Michael needs to eat people. And while Michael could leave through his door, Veneticus has power over him on the Island, so Michael cant due to Veneticus' sheer power/will of not letting him leave being too much. After a while though, it becomes clear Michael isnt backing down, and wont break or submit or stop trying to escape, so Veneticus starts to slowly be discouraged from manipulating him—and finally agrees to let him free. But, on the condition that if he wants to keep someone, Michael will help 'keep them in check' (because even if Veneticus has the power to just not let them free, he wants them to stop trying to leave at all, so he gets Michael to scare them or maybe lie to them about something so they'll be discouraged from escaping). Michael agrees (and yes, that does imply he is aware that Willow is on the Isle, and he does not care to do anything about it) to this, and gets let free at last—but he occasionally comes back, and starts visiting more frequently. And at some point, feelings develop between them both (Veneticus becomes more clingy, and Michael seems more willing to spend longer time on the Island during his visits)—but Veneticus only finds a word for it when a new visitor shows up, explains the concept of romance and relationships to him (he forgot societal concepts due to his severe memory loss caused by Desolatus, so he doesnt know what either of those are), and then that person dies from trying to escape from him and falling off a cliff. Veneticus decides he wants a lover—and wants to try that with whoever he sees next. But Michael happens to show up after that, so he decides Michael would be the perfect option (since he likes him anyway). Michael isnt uninterested, but Veneticus is clearly inexperienced due to how clingy and intense he is being about the whole thing—and he is also mostly just repeating whatever the visitor explained about romantic gestures or traditions. But, Michael agrees to be his lover since he does love him deep down, and they both have a sweet little relationship for a while until Michael dies. Veneticus feels grief for him upon learning about it from Helen the Distortion, and tries to see if maybe she wants to be his lover. But, she says no, and since he learnt that the Spiral wont be intimidated by him, he respects that. He ends up clinging more to Willow in this AU after Michael's death, so Jon has a harder time convincing him to let her free whenever he comes to rescue her (after Distorted Helen tells him of the Island and where shes been all this time). Veneticus also isnt sure how to process grief as an emotion, and doesnt really know what it is, so as a partial coping mechanism, he just talks about Michael a lot to Willow, and also wont really let Willow be by herself—often forcing himself into spending time with her more often than he normally does.
Even when Michael has a rough start with him though, I think he wouldnt exactly be all that nervous around him. He just knows he cant risk being on the Island due to the 50/50 chance of either not being able to leave, or not being able to enter. So thats more why hes so frantic about it, and why he seems a bit nervous around Veneticus. Hes more scared of the Island than he is of Veneticus, since to him, Veneticus is just its 'host'—the Island is the real Parasite he needs to watch out for and be careful of, since it can effect even him if hes there for too long or if hes not careful.
