Soul Hackers 2

Easiest way to get this achievement is to get one or two demons that have the ability to repel any physical attack or any magical attack for the whole party (can't combine abilities and only lasts one turn, doesn't reflect almighty damage). Find a demon to fight that will only attack with either physical or magical abilities and keep casting the reflect until they kill themselves. Very useful if you haven't already gotten this by late game with op characters.

Some demons have natural reflection for their resistances but it's hard to get enough for all teammates to properly reflect the damage as it's random who gets attacked.