Hi to all!
Since quoting all involved posts would make a really large post here, I wade right into the discussion.
When it comes to the question who of the PC leadership is more despicable, Kath and(!) Chuck are currently in the lead. Going by our current game knowledge level, August is the least one. He might be a mobster and a pimp, but he goes about it like the shady, criminal businessman he is. As long as business is running smoothly, he does not care what the house girls or carnations are doing in their freetime. If we are on good terms with him, we also learn that August is rather selfaware, he even tells us himself that he is a ruthless, bad person and that is was mistake to pressure himself back into Hana´s life the way he did it. In a talk with Otto he laso mentions that he fears that Kath and Chuck are starting to loose it. He started to love Hana as well, when at first he was simply interested in his legacy. But it becomes clear he loves his daughter now.
INO August is currently the only PC leader who might come out of an "upheaval" still in a position of strength, making a deal with the winner. That is not a surety and the likelyhood of him being removed is higher, but August is the only one I see who could get through at current lore.
Chuck´s mental conditions are more of a mystery, just blinking up now and then. But what we learn now and then is horrifying. August hinted at being afraid of Chuck when he is in one of his "special moods", which are getting more frequent, some house girls fear Chuck like no other patron or PC employee. If what we learn about Chuck from Abel and Sophia is just halfway true, that is bad enough and Sophia´s encounters with him strongly point towards it being true.
One example is that Chuck is sad at the thought, should he ever win against Sophia, he has to hold back from imparting lasting damage since Sophia is too valuable.
Abel said about Kath she has the same nasty disposition as Chuck, but none of his acomplishments. It is clear you should tread carefully around them. The main difference between Chuck and her is that he still has some grip on his sadism and mental conditions in so far Chuck let´s them only free under certain circumstances. He is as nasty and despicable as Kath, just handles it differently.
Kath is a nearly textbook example of a successful sadist in a position where there are only few ways to attack her. While she loves her husband as much as a fullblown sadist can do, he is also a functioning shield for her. Corrupting her sister´s help organisation to funnel herself a steady supply of helpless, desperate people to torment and live out her sadism to the fullest shows Kath has already passed the moral event horizon.
She lives for and enjoys destroying the life of others, which has been hinted at and shown several times. Currently she wants to destroy the lives of Veronica and Felicia badly, because both "disrupt" her "fun" by being not easily tormented.
And another near textbook behaviour of Kath is her power play in the club coming up soon. For whatever reason, the way this works is not fully understood today, very successful sadists often start to take unnecessary risks or trying to get more pieces of a "given cake", when they could simply be content and save in the actual situation. While drunk on power certainly plays a role, it does not explain everything.
Here in PC Kath shows this. She is in a secure position were she could keep going on destroying lives for decades to come, but she has started a power play to take over sole leadership of the club.
As for the sex drug Sophia invented, we have to remember that there are several versions existing. We have the "old" version which has been in use in the club for some time. And we have the "new" further developed version, which is stronger, looses less to no efficiency over time. This improved version is the one Sophia self-tested and the one in the syringes Kath has for the "reward" of Edwin. This is clear by her comments on the potency of it.
Naturally Sophia has full access to it too, it´s her invention, even the better perfume version in contrast to Kath, who has only the old perfume.
When it comes to Abel, Sophia and their involvement in the club, at current knowledge we have I theorise the two doctors are on a crusade of their own. They despise the current PC leadership, Sophia knows much about Chuck´s former victims, something that would be superfluous to know for a scientist hellbent on her project. Them testing the drug at the club is an unnecessary exposure risk, they have black ops labs of their own. While they help Kath currently, they also clearly have plans of their own for the club. They are the "Wind of Change" coming in.