Come now, [@LovelyAnastasia], this isn't Yandere Sim XD But it would be really interesting to have a murderer in the mix, though. Seriously, imagine when their significant other discovers they're dating a killer! What would they do? Try to convince them to stop killing? Dump them and hope to Hell they don't go on a murderous rampage? 

Ahh, psychopaths... Gotta love 'em.