Hamato Karai was an ally of the Turtles along with being the leader and founder of the Hamato Clan. She is also the daughter of Foot Clan leader Oroku Saki, who later became her most hated enemy, the Shredder.
She is a tall and slender Japanese woman, with long dark hair pulled in a high ponytail.
She is caring, kind and nice, however she can be strict and serious if the situation demands it. She is also grandmotherly to the turtles, she is shown to be proud of who her descendants are. She has shown to be able to inspire and motivate them as shown with Raph and even with April who she let join her family. She is very dedicated to her family, having sacrificed herself twice to save them, the first time was to trap herself while holding off her father for eternity and the second time after being unintentionally released along with her father and finally let her life end for them, but dying did not stop her from being with her family, as her devotion to them continues with her as a spirit.
- Oroku Saki/Shredder: Oroku Saki is Karai's father, who once founded the Foot Clan. She deeply cares for her father and she becomes devastated that her father was consumed by dark armor that was given by horrible Oni. She founds the Hamato Clan and sacrifices herself and she and her father were banished to the Twilight Realm. She along with her family destroyed the shredder once and for all and Oroku Saki is freed. Karai lovingly hugs her father and thanks her descendants, and she, her father and the other ancestors disappear.
- Hamato Yoshi/Splinter: Hamato Yoshi is her last descendant along with the turtles. Karai soon meets him as a mutant, but she becomes dismayed with Splinter for not teaching the turtles Hamato Ninpō. Splinter helps Karai to stand up on her feet.
- Mad Dogs: Mad Dogs are her latest descendants.
- Donatello: Donatello is her descendant. Karai becomes confused with technology since she has been gone for 500 years, but is amazed by it, which Donatello becomes so happy that he finally got some respect from the elder generation. Despite this, Donatello still cares about his grandmother.
- Leonardo: Leonardo is her descendant. Both get along very well as both having a loving and affectionate relationship. After Shredder arrives to destroy Karai, Leo protects her and teleports himself and Karai to the lab where he asks Sheldon to protect her. Leo and Karai share a heartily embrace and smile at eachother. Leo becomes heartbroken that Shredder murdered Karai in front of him and his horrified brothers. Leo, who still very much loves his grandmother tries to go after and save her, but Raph exclaims that Hamato must live on.
- Michelangelo: Michelangelo is her descendant. Both get along quite well, since Mikey had a drawing for Karai about her family, to which Karai gives Mikey a gentle smile.
- Raphael: Raphael is her descendant. In Anatawa Hitorijanai, Karai shows an affectionate support to Raph saying that he is never alone. Raph and Karai get along very well.
- April O'Neil: Both share a caring and loving relationship as Karai assures her that she always was a member of Hamato Clan. As she succumbs her fatal wounds, she dies as her spirit enters April.
Karai was born to her unknown mother and her father Oroku Saki. When the clan was attacked, evil oni gave her father the evil dark armor, which causes him to become evil; this led to Karai founding the Hamato Clan. She sacrificed herself by putting her and her father into sword in the Twilight Realm.
E-Turtle Sunshine of the Spotless Mind - After freeing the sword and Karai reveals herself, she asks them what have they done, she then faints at the end of the episode.
Shreddy or Not - After waking up, she realizes that Splinter and the turtles are her descendants, to which she tells them her story afterwards. After resting, the turtles spend the time together. When she is about to train them, Shredder arrives , fights and eventually stabs his own daughter, destroys the lair and S.H.E.L.L.D.O.N. With lair is destroyed, S.H.E.L.L.D.O.N decapitated, the turtles leave sorrowfully, but not before Karai tells them they are not alone.
Anatawa Hitorijanai - April comes back to the in ruins lair where she found near death Karai, who dies and her spirit enters April to which she gives her her knowledge and power. Later, April finds the turtles and while meeting with Raph, she tells him again that he is not alone, which finally gives him the idea to trust his family completely. This allows him and his brothers to access the clan's ninpo and be ready for their upcoming fight with the Shredder.
Rise - After fighting off the Shredder, turtles have some backup, Hamato Clan ancestors' ghosts come to give them a hand, with Dark Armor is destroyed, Oroku Saki is back and Shredder is dead once and for all. Karai tearfully reunites with her father, thanks the turtles for their help, before she, along with her father and descendants disappear.
Hamato Ninpo: She is the one who knows the Ninpo to defeat her father. With this, she has the ability to enhance her agility, strength to extreme levels and become incredibly swift. This also allows her to create a weapon from anything within her hands, as shown when she turns Donnie's self sculpture to create a dagger powerful enough to temporarily puncture the Shredder's armor. She can also use somewhat of a telekinetic ability when she turns blades made by the Shredder against him and even make him implode temporarily. It is unknown what her full potential is with this power as the Shredder implies that she has gotten weak, along with where this power comes from scientifically, besides spiritual connection.
"Get away from my family"
- Like Hamato Koji in the 1987–1996 animated TV series (who was the founder of Yoshi's Clan, the Foot), Karai was the founder of Yoshi's Ninja Clan, the Hamato Clan.
- This is the first television version of Karai to be biologically related to the Shredder, and the second version overall to be related to him after Oroku Karai in the IDW comics.
- She is also the first version of Karai to be the biological daughter of the Shredder.
- She is also the second version overall to be biologically related to Splinter, and through her, Splinter and the Turtles are the first versions of their characters to be directly biologically related to Oroku Saki.