Just set
Damage to Pals Multiplier 5
Damage from Player Multiplier 5
Now you are doing 25 time more damage.

If you want pal to still hit each other normally, then set
Damage from Pal Multiplier 0.2

And for player to take normal damage
Damage to Player Multiplier 5
However, Human NPC actually count as player. You will hit each other 25 time harder lol