So since Evelynn requires seducing to kill humans...

One might say it was a... family affair.

kinky shit*[sg-jinx]*

I was wondering the same thing. It's possible they committed an act of lust on their own, like one or both of them had an affair and then Evelynn came along (possibly seduced one) killed them, and then the other walked in and with their lustful sins fresh in the air and as a result Evelyn was able to kill them too.

I mean I guess so? I assume she uses magic to aid in her attraction. I doubt just being really hot would get both of Vayne's parents.

I think I saw a fanfic along those lines once.

Honest answer: doubtful.

If Tahm's lore is anything to go by, he made a deal with that one gambler and was able to kill & eat both he and his wife as a result. So it wouldn't surprise me if Evelynn's contracts functioned in a similar matter. IE - kill your buyer but get a little leeway with their loved ones for that extra suffering.

I find it more likely that she seduces one of the two and then kills them both. Kinda like what's happening in her splash art.

Seducing shouldn't be the main method, just a way to bait some easy to fool prey, but she does have a shadow form, that seems vicious enough to rip Batma....Vayne's parents to pieces without needing to seduce anyone