Abyss is becoming more and more cringe for duo/trio 4* runs, with HP sponges that have jank hitboxes and refuse to group. That 12-1 is awfully designed.
It's debatable whether C6 Chevreuse can even be considered a 4* unit, but it is what it is ¯\_(ツ)_/¯. She's the result of hard-pulling on the Raiden and Kinich banner even though I play neither of them.
0:00 12-1
3:16 12-2
6:10 12-3
8:55 Build
10:42 No BP, weapon banner etc.
