I don’t like how people think poison is a cowardly way to kill. I love the thought of killing with poison. The sight would be almost romantic. Almost like a sad pitying romance.
Poison could be effective through a small cut of the skin, hidden in a drink for instant effect, hidden in food for later effects, Etc. The mixes of poison could differ making different reactions in the victim. How is that not interesting in itself?
Then the thought of cradling the victim as they die. Having them look at you while gasping for air, seeing them realize what is happening to them and what you’ve done.

It’s not even a hateful/vengeful murder death feeling. It feels more like, a rare opportunity. A sad open person trusting the wrong person then fading away in my arms.
It’s an odd/interesting way to kill. I’d use it..