[@Crimmy]Same way it works in Persona 2. Two characters use specific spells (ex: Agi and Agi) and they do a combination attack that's stronger than both combined. I was thinking skill mutation could only change a person's skills into one of the opposite element. Ex: A wind user's skills could only be change to thunder etc etc. I was also thinking that these could change resistances in the same way it changes skill elements to make it more balanced 

And didn't you see? I changed the picture to its namesake. It's kind of on the nose since there isn't exactly any "fan art" of Hindu gods, but I'll change it again if it's a problem.