!!Ken Ogawa
* CoolMask: One that shows his face and conceals it all at once.
* CoolSword: He has several of them, in fact.
** AncestralWeapon: The Ninja Blade, a katana that remains sealed for much of the game. When finally unlocked, it provides PowerAtAPrice.
* {{BFS}}: The Stonerender Sword, a massive claymore-esque blade capable of cutting through heavy armor.
* DualWielding: 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.
* ElementalWeapon: His various shurikens, which can be infused with wind, fire, and lightning, respectively.
* FumaShuriken: With TronLines that show which element it's currently infused with.
** KatanasAreJustBetter: The Oni Slayer sword, his default weapon.
* TheHero: An upright and outstanding ninja who retains his humanity instead of being tempted with power.
* MultiMeleeMaster: He's equally proficient with several kinds of swords.
* {{Ninja}}: [[CaptainObvious No, really???]]

!!Kuroh Sakamoto
* AlwaysSecondBest: 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.
* [[AndThenJohnWasAZombie And Then Kuroh Was A Mutant]]
* ArrogantKungFuGuy: Kuroh Sakamoto...who, unsurprisingly, turns out to be evil by the end of the first chapter.
* FaceHeelTurn: He becomes a host for the parasites. [[spoiler:Unlike Kanbe]], he did it willingly.
* MoreThanMindControl: Kuroh surrendered himself to the infection to attain more power.
* TragicMonster: Subverted. Kuroh actually accepted the infection to become more powerful.

!!Kanbe Ogawa
* AndThenJohnWasAZombie: He becomes one of the mutants. [[spoiler:The host for their core consciousness, in fact]].
* ArchnemesisDad He's Ken's father, and the main antagonist. [[spoiler:It's all part of a BatmanGambit to find the core of the parasites' consciousness]].
* AttackOfThe50FootWhatever: The form he takes for the final boss fight. [[spoiler:At least, the first stage of it]].
* BatmanGambit: He used his status as a ninja master to [[spoiler: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]].
* FaceHeelTurn: By the end of the first chapter, he's become the human face of the parasite outbreak.
* TheHeavy: The parasites are the real menace, but Kanbe is their most powerful human vector.