Kai is a secondary protagonist and major character featured in Heavenly Sword.
The adopted sister of Nariko, Kai is the sole surviving member of one of the many clans wiped out by King Bohan during his conquests. Orphaned at a young age due to the murder of her mother at the hands of Flying Fox, Kai was taken in by Nariko's clan when they found her in the wilderness. However, it was Nariko who forged a bond with Kai, with the former watching over the latter like an elder sister, due to the pair having similar lives (loss of their mother, outcasts from their clan, etc.).
Events of Heavenly Sword
During Heavenly Sword, the player is able to control Kai at different points throughout the game. The player controls her at four different levels during the game: three times as a sniper, and once during a Chapter entirely devoted to Kai, in which the player uses Kai's skills with a crossbow to defeat soldiers in Bohan's army during her rescue of Nariko. She is featured in multiple scenes throughout the game, and is present in the game's final scene, where she stands next to Shen as she sends Nariko's lifeless body drifting out to sea. It is also Kai who Nariko entrusts the Heavenly Sword to moments before her death, making her promise to keep the Sword safe.
Kai appears to be in her late teens, yet possesses a child-like outlook on life. Her level of immaturity can most likely attributed to the fact that her mother, as well as her entire clan, was murdered when she was young, thereby traumatizing her to the point where her mind created a sort of "happy place", where the problems going on around her couldn't reach. She isn't completely unaware of the violence around her or the seriousness of a situation, though; an example is in Chapter Three when she goes on a rescue mission to free Nariko from Bohan's prison. Kai's appearance seems to resemble her personality as well. She wears a ragged blue skirt and top to match, as well as a faded, torn red hat and worn sandals.
Although not possessing any skill whatsoever in terms of close combat, Kai's skill with a crossbow is virtually unmatched. Players can use the "Aftertouch" ability to guide arrows when shooting, which provides certain amounts of Glyph Points if guided to certain locations on an enemy's body. For example, a head shot is worth more Glyph Points than a torso shot, and so on. During Chapter Three, in which you control Kai for most of the sections, Kai is also able to stun enemies by leaping over their heads, which players can use to their advantage. Kai can also shoot her crossbow, which she calls, "Twing-Twang", at Heavenly Pots and earn Glyph Points while regenerating health. Finally, players can guide Kai's arrows through fire and into explosives, causing explosions and immense damage to the surrounding area.
During the game, Kai surfaces as a major character, appearing in at least one scene in every Chapter. She even manages to kill another major character, Flying Fox, as she hangs in a noose from his birdcage, earning redemption for her mother and her clan in the process. In one of the final scenes in Heavenly Sword, Nariko transfers the last of her power to Kai, before giving the Sword to her and dying. Kai is depicted in the final scene as well, being comforted by Shen as Nariko is sent out to sea in a boat, covered in rose petals.