Hart Tenjo

Heart Tenjo known as Haruto Tenjo in the (japanese version) is Kaito Tenjo's younger brother. He possesses a power that Dr. Faker abuses in order to accomplish his plan of conquering the Astral World, and collecting the "Number" cards. He holds a strong connection to Astral.

Personality
Haruto appears to have a split personality. When not using his powers, he tends to act quite vulnerable, usually staying in bed, or looking down at Heartland from the Heartland Tower, wondering why he can't enjoy laughter like the people who attend the Heartland Fairground.

When using his powers, Haruto sadistically laughs at the Astral World's inhabitants' screams, saying that he "needs more screams" as that is what comforts him.

Kaito has also stated that Haruto hasn't been his usual self as in the past, as he used to enjoy laughter and was playful and talkative.

Abilities
Haruto possesses a mysterious and strange power that can create paths to alternate realities and teleport to another location. He also can transfer his power to his brother.

History
In the past, Haruto lived with his brother Kaito in a small, wooden villa where they would play all day whilst Haruto drank his favorite drink, hot chocolate. This happy life was however, disrupted due to the presence of Haruto's special powers. Mr. Heartland appeared before Haruto and his brother, and told Kaito that Haruto's powers are useful for the world and that Haruto must go with him per Dr. Faker's orders.

Some time later, Haruto was visited by his brother at Heartland Tower, but he couldn't remember Kaito. Angered, Kaito demanded from Mr. Heartland to know what he had done to his brother. The latter answered him Haruto is able to communicate with the spirits of the Astral World. In order to save their own world, they must destroy the Astral World, and Haruto had been chosen for that purpose. As Haruto's soul had already left, the only way to heal Haruto is the gathering of one hundred "Number" cards. Upon hearing that, Kaito agreed to become a Numbers Hunter.

During one night at Heartland, Kaito tried to escape with Haruto. As they were hiding from Heartland Police, Kaito gave him his favorite candy, caramel to cheer him up. However, they were found soon. Kaito was subdued, while Haruto was taken away from him. Seeing his brother being restrained, Haruto used his powers to knock the police who were guiding him off of the tower. But they were both captured once more.

Yu-Gi-Oh! ZEXAL
After hunting the "Numbers" of an unlucky Duelist and informing Mr. Heartland about his capture, Kaito returns to the Heartland Tower in order to check up on Haruto. He finds Haruto stood at the window of the tower, staring blankly down at the people enjoying the Heartland Fairground and asks Kaito why they are laughing as he doesn't require laughter, only screams to which Kaito shows displeasement. He then asks Kaito if he is weird, to which Kaito says that he is simply in a bad dream and that he will one day wake him up from it.

During Kaito's Duel with Yuma Tsukumo, Haruto is ordered to send the trash collected by the Litterbots into the Astral World again. During which he experiences severe pain in his head, causing him to collapse and cry. Orbital 7 monitors Haruto's situation and informs Kaito, causing him to cancel his Duel with Yuma in order to run to his brothers aid, saving Yuma and Astral from not only losing their "Numbers", but also their lives.

After his trauma, Haruto spends a number of days in bed. To keep Haruto relaxed, Kaito stays at his bedside, making sure that he is comfortable in every aspect, even to the extent that he has a holographic scenery of their old house surround Haruto's room. Despite being ill, Mr. Heartland interrupts and states that Haruto must use his powers. Despite Kaito's protests, Haruto says that he will use his powers as they are causing good for the world, to which surprises Kaito. Haruto then walks with Mr. Heartland who tells Kaito to continue collecting the "Numbers" if he wants to save Haruto in time. The two then disappear through a portal. Some time later, Haruto is seen sleeping with Kaito watching over him.

Later on, Haruto sees Kaito exhausted from collecting the "Numbers" to heal him. Haruto then sneaks away from the Heartland Tower, and by chance meets Yuma, Astral and Tori. Amazingly, Haruto can see Astral, who in turn seems to know Haruto's name. Moved by Astral's wish, Yuma takes him to his home, but in the way, they find Gauche and Droite, who were searching for him. Haruto then creates a wave of energy and flee with Yuma and Tori. After Yuma agreed to take him to Kaito, he panicked when a helicopter (which was in fact piloted by V) was about to land. As a result, Haruto unleashed his powers, but Yuma calms him down with a caramel. V then comes out and uses his Crest to take control of Haruto, whom goes on the helicopter with him, and they leave.

Yuma and Kaito then join forces to go rescue him, breaking into an abandoned Gallery, where they meet and confront IV and III. While the four Duel, Tron begins a ritual to extract Haruto's powers.

While Kaito is fighting, at the moment where he's about to lose and embraces the spirit of never giving up until the very end, Haruto resonates with his brother and, bearing in mind that Kaito has always been there for him to protect him, Haruto decides to fight to protect his own brother as well. As a result, Haruto's powers are transferred to Kaito, allowing him to Xyz Summon "Neo Galaxy-Eyes Photon Dragon", forcing the ritual to end, and leaving Tron only some power. Haruto had then been left in critical condition, and was rushed to the hospital.