The dying photographer handed him a photograph of his family and Joker decide to protect his family in order to atone for his death. The Joker adopted the name Hajime Aikawa, a free lance photographer, after this incident. Though he thought less of humans originally, Hajime's time with the young girl and the widow of the photographer, Kurihara Haruka and Amane, made him realized that the humans were good beings and wished for himself to be human instead of being the Joker. Hajime's feelings eventually expanded to Kenzaki, who became a dear friend of his, and then Garren. But when the Caucasus Undead takes most of his cards, the sealed Mantis Undead among them, it causes Hajime to regress back into the Joker after attempting to resist until Leangle unseals Hajime's cards and use the Undead against him. After managing to reseal them all, the Joker goes on a rampage until he is provided with the Evolution Paradoxa, allowing Hajime to have full control of himself.
However, this lasted until Giriffa Undead was sealed, with Hajime losing control and his impulse as Joker comes forth with the Stone of Sealing creating his army of DarkRoaches to eliminate all humans. Kenzaki is the only one to combat him head on. Kenzaki sacrificed his humanity in order to save Hajime and in turn, the Battle Fight resulted in a stalemate as they part ways to keep it so. In the end, Hajime is allowed to keep his Human Spirit card to maintain his disguise and stays with the Kurihara family for the rest of his life, but still remembers what Kenzaki has done for him.
In the Missing Ace movie, Kenzaki was forced to defeat Hajime and seal him with Lightning Blast. Though in seemed to be over, the actions of the Albino Joker four years later forced Kenzaki to have Leangle release the Black Joker from his card prison to aid in protecting Amane as his true self and later as Chalice. In the end, Hajime sacrificed himself by switching places with Amane to save her and give the other Riders an advantage over their enemy. His spirit was later shown watching over Amane, the girl assured by Kenzaki that Hajime will always be there.