Sometimes I find myself wanting the fl and diable to end up together then I remember what ...

piece of shit where???

Did you not read the beginning of the story?

I think they ment like how he didn’t really help in the 1st timeline

No, he was the cause of all her trauma.

We don't know what the plot twist is yet, though?
It could be that Diabel was lying through his teeth, and that he actually died and became a devil on the previous battlefield.
...Or, he had an unspeakable contract with another demon where he couldn't interfere until now... or something similar.

I'm hoping for a plot twist than, because I really want them together.

Well. Ig he is a piece of shit

yea just you wait

to be fair he was apart of it but he didn't cause everything, it's not like he was on the Russell's side

Just because it may not be completely his fault doesn’t change the fact that he is still to blame.
Why is someone always trying to justify another person’s messed-up actions?

idk why you're acting like he's the one behind everything, he didn't plan the attack on her family or anything either. His actions that are known to us rn is that he's a devil and his devotion to the fl was for funzies all along but throughout the story we obviously no it's not true and there's more to his character then it's revealed

I clearly stated that he isn't completely at fault,