Leo Akaba appears as a middle-aged tan-skinned bald man with light blue eyes, who wears a purple colored militaristic outfit with several black buttons which resembles the outfit of Vellian Crowler, a purple cape with a black ending, and a pair of grey boots. He also has a black belt with a red line which both end in a button on the front, and what appear to be red circular strings across his chest with a pair of black gloves on his hands. His perhaps most noticeable traits are the armored plate at the left side of his head with what appears to be a red circular lens, and pronounced blood vessels on the top of his head.
Leo originally hailed from the Standard Dimension, and was the original founder of Leo Corporation. One day, he suddenly left for the Fusion Dimension without telling anyone in his family, thereby abandoning the company. He took control of Duel Academy and used it as a frontline base to enact his plan to unite the Four Dimensions.
Eventually, Declan stumbled into Duel Academy through a teleportation device, but Leo caught up to him. Selena, who was attempting to escape with Declan's aid, complained to Leo about being stuck at Duel Academy while her comrades were preparing to attack the Xyz Dimension, but he refused to add her to the vanguard squad. Declan also protested that Leo had abandoned Leo Corporation, to which Leo asked him if he had crossed dimensions just to find him, confusing Declan even further. The Obelisk Force troops apprehended Selena, and Leo told her that he would definitely find her and bring her back to Duel Academy, regardless of where she ran. He then used a wristwatch-like device to send Declan back to Standard, but not before telling him about the Fusion Dimension and about him using Duel Academy to help him bring the worlds together.
Leo was first mentioned by Shay when Declan first confronts him. Both Shay and Declan consider Leo their enemy, with Declan insisting he is preparing Duelists to confront and defeat Leo.
When Declan and Shay were watching the Duel between Yuto, Sora Perse, and Yuya Sakaki, Yuto revealed that Duel Academy invaded the Xyz Dimension. Declan stated that this was due to Leo Akaba's ambition. After Sora was transported back to Duel Academy within the Fusion Dimension, Leo was watching over a machine absorbing cards into itself. At the time, he was informed by the Aide that the forced return program activated once Sora revealed his mission to their enemies within the Standard Dimension. However, Leo clarified that the Standard Dimension was not their enemy and that investigating Sora's memories would explain the situation. After doing so, he informed Yuri about Zuzu Boyle's existence, claiming that she might be the fourth piece that he was looking for. Because of this, he ordered Yuri to bring Zuzu to Duel Academy.
When Sora asked Leo directly to let him return to Standard, Leo granted his request, under the conditions that Obelisk Force would accompany him and that he would retrieve Selena and bring her back to Duel Academy.
Friendship Cup Finals
After hearing Dennis' report that Zuzu and Selena were in the Synchro Dimension's City, Leo gave Barrett a new mission to go to the Synchro Dimension with the Obelisk Force and capture Zuzu and Selena. He also informed him that Yuri would also come to the Synchro Dimension.
- According to his voice actor, Leo is a character with high importance and a great impact to the story.