Rock Gaidan is a Genin Master of Masters. He is a rogue Genin who left the Hidden Villages because they were "boring". Currently, he intercepts all kinds of missions, especially S-ranked ones, for training.
His first and foremost ability. He has the ability to self-resurrect courtesy of his worldly love. This love helped him make a deal with an extra-terrestrial entity, which granted him his wish.
This granted him Regenesis' regeneration, which activates at the moment of death. This makes him immune to soul-related abilities.
Gates of the Heavenly Kaio, Deathly Daio, and The Middle Way
A remarkable series of gates consisting of 24 levels each, unlockable depending on the great deeds he has done in the world. The Heavenly Kaio Gates grant pure Yang Chakra, the Deathly Daio Gates grant pure Yin chakra, and The Middle Way Gates grant pure power and represent the number of Gates Gaidan can keep passively active.
Use of these extreme Gates lead to death, except, Rock Gaidan cannot die.
He only uses these Gates as a last result.