Universal FB/SS skill.
 

One of the skills that bring people together for fun is FB/SS. My suggestion is to add universal skill that can be used regardless of the weapon, with a damage percentage that does not affect the balance of the game, or affect Trojans unique skills.

As a ninja who has epic weapons, I wish I had an FB/SS kind of skill to play with others. And I would keep it with 1 line instead of 3.