I know I shouldn't say this but...

o_o !!! to kill your family, friends and pets if you disobey him? the treat you like a possession not a human being? to overpower you whenever be feels like it disregarding your feelings entirely if they don't agree with his?

.......... I get that he's handsome, but ..... honey, noooooooooooo,

no one deserves to be treated this way.
and he's a Psychopath. He has no empathy or compassion. Unless he thinks you are important, you are a pawn or dispensable.

（￣へ￣）

But.... I can change him :)

That's what his concubine thought too.
He cuts her to pieces.

Just a mother hen worried about others, this kind of personality does not respond to how other people perceive them. Their ego is self directed, and there is a chance that someone MIGHT spark their interest enough to be worth their time, but that is all based on criteria they themselves invent, and not on what the other person wants or is willing to do for them.
I know I know, I'm being too serious, but this is an honest PSA. Do a little reading on "being in a relationship with a Psychopath/ Sociopath/Narcissist"
and realize that the amount of damage, both physical and psychological that these types can inflict is not worth it (just cuz they might be good looking).

In my opinion, this is a tragic story. One in which the MC is shackled by the MCxML1 trope of almost all BL stories. There is only a little growth for the MC, enough where they realize they have just enough worth to stop the ML from indiscriminately murdering people. That's how he chooses to redeem his choice to remain with this murderer Emperor. The Emperor, on the other hand, is obsessed with the MC, partially because of the toxin, but also because he is difficult to control and won't bend to his will no matter how much abuse he suffers. He will eventually change tactics so the MC doesn't struggle to get away from him anymore (but that's only waaaaaaaaaaaaay towards the end. In for a LOT more rape before then).

This level of abuse should not be rewarded, but that's what happens in this story (as it does in many too many RL relationships). *sigh*

Please love yourself enough not to fetishize this kind of character.

Awhhhh, thanks btwww