Subscribe to download
Backstab Mechanic, by Mafe

Simple mod. Ally or foe, now all entities when attacking the back of a target, will deal additional damage by 5% of the target ACTUAL HP. You can see this on the damage preview.

Some rules of it:
-- Dmg is 5% of target ACTUAL HP
-- Bosses or targets resistant to HP based attacks will be immune to it
-- Having "Backstabber" passive equipped raises the Backstab dmg that the unit can have to 7% and allows you to bypass the immunity of targets resistant to HP based attacks