Ancestral Weapon: The Ninja Blade, a katana that remains sealed for much of the game. When finally unlocked, it provides Power at a Price.
BFS: The Stonerender Sword, a massive claymore-esque blade capable of cutting through heavy armor.
Dual Wielding: The Twin Falcon Knives, a pair of kodachi (short swords) with high-tensile wires in the blades that let them double as whips/grappling hooks.
Elemental Weapon: His various shurikens, which can be infused with wind, fire, and lightning, respectively.
Always Second Best: The reason Kuroh Sakamoto let himself be infected was because he always felt inferior to Ken and wanted to use the parasites to surpass him.
Batman Gambit: He used his status as a ninja master to make himself a host for the parasite queen, trusting his own toxic blood to weaken the monster to the point where his son could finish the job.
Face–Heel Turn: By the end of the first chapter, he's become the human face of the parasite outbreak.
The Heavy: The parasites are the real menace, but Kanbe is their most powerful human vector.