While using his Quirk, Nagamasa can manipulate the growth and movements of all of his hair. His hair is unusually resilient and indestructible, making it impervious to any harm or damage.
His Quirk is very powerful, as it allows Nagamasa create an armor around his body and incapacitate a large number of enemies at once by capturing them within his extended hair.
The hair is prone to get tangled, which can be annoying for him. It is unknown if Nagamasa's usual hairy appearance is a result of his Quirk being activated or if it is his natural look.