Ayries_Jesea
I hate Nanatsu, but I think there's a character there who accumulates power with every hit he lands. Effect: With each successful hit increases the damage of the next hit by 20%. And increases with each ring the effect increases by 10%. Weakness: When a hit is received, the effect resets. This combines perfectly with the 6 eyes. And finally, make the six eyes a martial soul.
Just had a thought for a martial spirit in dd. An anime called Plunder(or whatever) has a sort of pvp system where people can earn and steal stars that signify their strengths. MC of the story used some Greaves which had a few thousand stars(average people have a few tens maybe hundreds) and he could step causing showckwaves