SINNER: Sacrifice for Redemption

For this achievement you basically just have to kill one of the Levins pretty quickly. I focused on the one with the axes I think it's indok. When the other one comes out just keep focusing on the original. As long as one's dead you can take your time on the 2nd.

Nikolai420 is right but if I could add a few things:

1) kill the axe lady first because she is the hardest. this is probably easiest done by beating both down with the big sword and saving your spears. When both appear, you get a few seconds of easy melee before you need to back off and start throwing spears at her. 10 spears can take her out from a distance and if she gets too close you get to stun her at least once. RT + X if she has a sliver of health left.

2) for killing the second one there is a simple pattern to follow. the three attacks (besides melee if you get in range) are:

A) a lightning attack that explodes in all directions which can be dodged by keeping your distance by rolling/sprinting away from the original strike location

B) a lightning time bomb attack that drops little lightning runes around you that will explode shortly after landing. This is your best time to RT and mash X to hit him 3 times. Retreat because of attack C

C) a lightning explosion that erupts around her. If you are following up from the strikes above, you can roll out of the way in 2-3 rolls (pay attention to the edges and try to keep her in the center by going in circles) When the lightning explosion starts you can count to about 3 and start charging in to get a quick RT + X attack in there.

Rinse and repeat and shes is dead. If she is not doing any moves then you are too close to her and she will just spam melee. I found her so easy I kept killing her first and then getting wiped by the super version of the axe lady. The key is to save spears!