Love is Overkill

Meet S'more Milwalky, a genius scientist at Deslike Prison, otherwise known as Dead End Prison. S'more has been grinding away nonstop with research and work, leaving her little chance to fall in love. However, one fateful day, when the executed assassin known as "Painkiller" is brought into her lab, S'more accidentally uses her Secret Elixer on him...

(Source: MANGA Plus)