Reiji Akaba/Relationship

Himika Akaba
Reiji is shown to be good terms with his mother. Both of them agree on what they are doing and are shown to have a normal mother-son relationship. Also, Himika would often call him "Reiji-san", which is a polite suffix in Japanese that address to person who is respected, showing how much Himika greatly respects her son.

Reo Akaba
Reiji considers his father as an enemy, disagreeing with his goal to unite all four Dimensions. Whenever the subject about his father's goal is brought up, Reiji clearly showing his anger, as oppose to his usual calm demeanour. It is unknown how Reo feels about his son, but Reiji stated to Shun that he doubts his father would care about his well-being.

Reira Akaba
Reira admires and looks up to his older brother, referring him as "Nii-sama" in Japanese. While he is very shy and reclusive to others, even his to own mother, he seems comfortable whenever Reiji is around, as shown when he Dueled Ayu; he at first reluctant Duelling her, but when he saw Reiji watching his Duel, Reira quickly became more focus to win, showing that he doesn't want to disappoint his brother. Reiji has high hopes for Reira, though not as strict as Himika, complimenting and patting his head when he won. Reiji is also confident with Reira's Duelling skill when the others doubted him, defending Reira when Shun and Shingo objects his participation in their trip to Synchro Dimension.

Yūya Sakaki
Reiji developed a quick interest in Yuya, the founder of Pendulum Summoning. Despite there are many talented Duelists, Yuya is the one who he has his eyes on the most. He asked Nakajima to observe and report any progress on Yuya's Duel and even asked for the Duel Committee to permit Yuya into entering the Championship despite lacking the condition to enter (Yuya refused this offer though). Although being one of Yuya's rival, he doesn't show any dislike towards him and even defended him when Mr. Sawatari accused Yuya as the culprit behind Shingo's attack. Although he views Yuya's resolution is naive, Reiji doesn't stop having high hopes for Yuya due to his growth, going as far as to provoke him during their rematch to make Yuya join Lancers since he is necessary to fight the Fusion Dimension.

After their first Duel, Yuya quickly views Reiji as one of his rivals and strives to grow his Pendulum Summoning not only to become the best Pendulum Summon Duelist but also to defeat Reiji. Yuya at first respected Reiji as a great Duelist, but any respect he has for Reiji quickly fades after he knows that Reiji purposely holding Battle Royale to test which Duelist is suit to become part of his Lancers, making him partly responsible for turning most of Battle Royale Duelists into cards.

Nakajima
Nakajima is Reiji's closest subordinate. Nakajima is shown to be very loyal to Reiji, obeying his every order and dedicate himself to accomplish it. Reiji also trusts Nakajima to do his work, personally asking him to give report of any activities concerning Yuya or cases happening in Maiami City to him.

Shun Kurosaki
At first, Shun was targeting LDS in order to capture Reiji as bargaining chip to save Ruri, but they then work together after knowing they are sharing the same goal to defeat Reo. They're not in a really good relationship due to their differing ways of handling the situation, though Shun mostly relents to Reiji's order, knowing that his plan is for the best despite his own reluctance.