Ok how about this, the chakra shroud that i rambled about earlier is their only power, but a strong one. They use their willpower, or "will of fire" to create a shroud similar to naruto's While in it, all of their healing capabilities are near a level of high speed regeneration and all of their abilities are increased (ex: seed, strength) and genjutsu won't work because of the shroud somehow messing with the users flow of chakra. The shroud user could also possibly use the chakra as appendages like naruto does. This could combat tsukuyomi and susanoo and the speed could combat amaterasu. The shroud would be limited because it would take up a lot of chakra though. What do you think?