Zekka is a Karateka who first appeared in Last Order Book 10: Angel Goes Nova.
Zekka is widely recognized as the most powerful living warrior. He was a pioneer in developing Karate styles that could be used to fight modern cybernetically-enhanced foes along with Tunpo. They were both students of the same Karate master on Mars who gave them their Karate names and assigned Zekka to develop a "Dragon-Slaying Method" and Tunpo to devise a "Tiger-Killing Fist" before apparently killing himself by jumping down a cliff. Since dragons are purely mythological and tigers were long-since extinct, he meant that they were to develop techniques to fight super-human foes. He faced Tunpo in the third round of the second Zenith of Things Tournament. Since they were equally powerful, the fight resulted in a draw, damaging them both severely as well as breaking one of the Tiphares mooring tubes. After that, Zekka and Tunpo parted again, Zekka making further cybernetic enhancements to himself, including a new Fizziroy type body, exchanging his flesh-and-blood brain for an artificial one eventually developing a massively powerful technique which he named "Dragon-Slaying Bone Crusher". Six months prior to Book 11: Angel Cake, he tracked down Tunpo to a cluster of Space-Buddha asteroids with help from Aga "Trinidad" Mbadi with the intention of fighting him. To his great shock and disappointment, he found that Tunpo had converted to Buddhism and become a Robo-Buddha. In a fit of pure rage, he destroyed the entire asteroid they were on using a single Karate chop. During the events of Angel Goes Nova, Zekka met Sechs, who also had a Fizziroy body, although a more updated version, and took an interest to him. Sechs attempted to punch him, but Zekka was easily able to block it. He then challenged Sechs to a thumbwrestling match, promising to fight him in a full-scale match if he could make him "get even a little serious". Sechs took him on and was defeated, but having used his Mini-Sechs module to draw graffitti all over Zekka's motorbike "Desecrator", made him furious enough to punch him through three floors. Impressed, Zekka promised to fight him later. Zekka joined forces with Toji, a fellow Karateka, when he fought Anomaly during the third round of the tenth Z.O.T.T. and helped him destroy it. In Book 12: Angel Redux he joined forces with Alita when her team defeated the Jupiter team in the semifinals and Mbadi cancelled the tournament "for safety purposes". After Mbadi was convinced to let the tournament continue, he started assembling a new set of team members for himself and Toji. He ordered the potential recruits to prove their skills by fighting each other, setting of a free-for-all.
Zekka's fighting style has not yet been fully specified. He is a Karate master, but has not yet been seen truly fighting. Most of the time, he simply dodges strikes and may occasionaly perform single, poweful strikes. He has extremely fast reflexes and is capable of moving at supersonic speed. He is also very knowledgable about Karate and the Fizziroy body and is capable of performing "the legendary palmite", a technique which involves flattening a glass bottle using only the palm of one's hand. If it's done properly, the glass will be flattened and assume the shape of the palm print rather than being smashed.