>>280929909
Darkness is probably the strongest contender so far. Death however has experience in eating dick since the dawn of mankind.
It's a clash of the titans.

It's already been made obvious that PS are corrupt as hell (basically working for some old men in high government positions, not the public) + retarded due to taking all of the information on how to beat the Death Devil, FROM the Death Devil.
This is why Yoshida and Fumiko are so shocked and mind-broken when Death makes it clear that she was never serious about helping them. That was their one ace in the hole they thought they could count on.

>>280692691
I think Death may have run out of patience with Yoru. What use is she if she's not even willing to turn Denji into a weapon? She's uncooperative, reckless, despises humans, etc In every sense basically just an obstacle to Death's plan.
Yoru's only worth is her ability that she grants to Asa. So it's possible that Death would be fine with Yoru getting "put to sleep" for good as long as Asa retains her powers.

>>280378305
I think she may have given up on Yoru here. She might want to just turn all of her sisters into pawns at this point.
The weapons flying at them, seemed to stop until Yoru was unable to pull the trigger, after which she was "killed".

>>280325536
I believe only Yoru has the potential to be labelled the "King of Terror" by the end of P2, although I do think it's also likely that it'll be a currently unknown character that emerges as a result of the Four Horsemen's meddling.
Death is more so like a puzzle to solve for the protagonists or even herself, a ticking time bomb that needs to be defused somehow.
I don't see her as THE villain of P2 unless something drastically changes about her behavior/motivations (which is possible).