Yasuyoshi Sano (左 安良, Sano Yasuyoshi?), known as 'Aeon Clock', was a Storm Rider who was once a member of Behemoth. After Behemoth was disbanded, he was recruited into Genesis by Simca the Swallow and served as an ally to Kogarasumaru.
Sano appears to be a young man of average build and height, with short brown hair and grey eyes. He wears glasses and is normally seen in a suit or a tail coat. His shoes are ATs.
Sano was previously in Spitfire's team Coca Fire and desired to be the 'Flame King'. However, after Spitfire regained his title, Sano parted ways with the team and Spitfire (on bad terms) and later joined Behemoth.
Sano is next seen saving Kazu and Emily from Gabishi by freezing the latter in place with his "Time" trick. The two then enter into a high paced battle which both Kazu and Emily are amazed at. As the battle progresses, Sano analyses and reveals the true nature of Gabishi's Regalia, and takes the upper hand by stopping Gabishi's tricks before they even start. Towards the end of the fight, Gabishi pretends to be beaten back into an enclosed space, revealing that he can now start fighting properly as he is not a "speed-type" rider. Gabishi seemingly defeats Sano and is about to use is Regalia to remove the skin from Sano's face, when he is saved by Emily, jumping in and holding Gabishi still. This gave Sano time to grab a motorbike from nearby and bring it down on Gabishi's head, following up with his strongest trick, "Reincarnation". Gabishi however is still standing and is about to finish the riders off when Nue, fresh from being tuned, arrives and defeats Gabishi using his "Atmosphere Max" trick. Nue then tells Sano to call Simca and have Gabishi brought to "Big Bird".
It's later that Sano receives a call from his father, questioning him on the progress on his current project to capture the Sky regalia. Sano reveals that he has no intention of doing that, though only to himself. He then arrives in the nick of time to save Spitfire from the burning wreckage caused by Sora's Bagram. Nike then starts a battle between himself and the two Flame Road wielders. By combining their two Flame Roads, they create a powerful "Dual Road", the Apollo Road. Even with their incredible abilities, and total domination, Nike continues to rise uninjured. Revealing that his Jade Road is causing no harm to come to him, They are forced to take a short retreat back a few dozen feet, while trying to figure out a strategy to get past the Jade Road's ability. During this time, Nike launches a helicopter blade with his incredible strength. But it is intercepted by Ryō, who is killed by it, but not before revealing the weakness of the Jade Road to Sano.
Sora then criticizes her, causing Sano extreme anger. It seems that both Sano and Mimasaka were close, although the later envyed Spitfire for Sano only feeling free enough to show his true self by his side. Sano strikes Sora with an incredible strength caused by his anger, knocking Sora back, his hat falling off. It's then that Sora enters the fray, using his new legs as well as the stolen Bagram. Kazu, deciding to join in, does his best to assist the two Flame Road users. But they are ultimately forced back by Sora's incredible power after utilizing Bagram in a newly shown form.
He then acts as cover for Spitfire to take Kazu out of the battle and leave the Flame Regalia with him. Sano thinks to himself that the future Flame King has been able to escape from harm. Shortly afterwards, Spitfire returns and asks Sano to forgive him for getting him involved. Sano brushes it off, and the two have a heart to heart before Sano is unable to keep the combined power of Sora and Nike at bay. They are both pierced and hit by hundreds of rocks leading to the belief of their deaths although their bodies were missing. However, it is later revealed that he is still alive and working under the Takeuchi brothers.
Sano is later shown accompanying Orca on a hovercraft. Later, during a conversation that Orca has with Pyon, Orca indicates that Sano is helping Genesis locate Ikki's group, however, he has since disappeared again. Orca comments seem to imply that Sano's goal is to claim the Flame Regalia. Following this, he finally steals the Flame Regalia from Kazu while he was distracted by a storm. It has been stated that Sano has forty-eight different tricks/attacks.
The reason for Sano still being alive is a artificial body, covered in synthetic skin. When Ringo, Mikan, and Kururu raid the mansion, They fight, with Mikan ending up fighting Sano. He allows Mikan to kick him in the abdomen, breaking a device in his artificial body used by the Takeuchi brothers used to monitor him. When he informs Mikan of this, she stops attacking him. He tells her how his life is Ikki's "feathers." It is also revealed that Ryo Mimasaka is in a comatose state, who the brothers are using as a hostage to force Sano to work for them, and Sano is attempting to rescue her. He also tells Mikan, "My heart is still inside those wings engraved with the same time." (Confessing his love for Ikki) This invokes Mikan's normal expression for a surprised, blushing one. He then looks at her body from several angles, then randomly gropes her breasts and then suddenly asks himself why he did so. It is later revealed he placed a bug on her to tap to eavesdrop on the internal conflicts of Sleeping Forest. Once hearing Rika was pregnant while in the holds of Sora, he patched the line through to Ikki.
During Kogarasumaru's match against Sleipnir, Sano ascertains that Sleipnir is composed entirely of Brain Chargers from his family's research laboratories. With his maid, Aikawa Taeko, he rushes out to the site of their battle.Though it later turns out that Ikki had asked Sano to get supersonic airplanes so that they can reach to the battleship where Rika is held captive. Sano does the same as Kogarasumaru and Slepnir battle ends he reaches Ikki with the supersonic planes. They all head out to the battleship. Also he had asked his maid to put a microphone on Ikki so that he can hear whatever he is doing but his plan failed. He has also called out for help from all Kogarasumaru opponents to save Rika and help Ikki defeating Sora including Bando Mitsuru and Hanged Man. Upon arriving on the carrier he and Kazu used the time technique to cloak the whole team. Later he explains that heat or "flame" is the natural enemy of electricity immediately offering for Kazu to stay behind to defeat Nue. He also lectures his maid on what she wears on her bottom half. He joins with the rest of Kogarasumaru in searching for Rika but fails to realize they have been caught in an emeny's "run". Like the rest of the team he apparently does not notice as Kazu is captured.
Later when they finally realize Kazu is missing Agito suggests to leave saying that Buccha and Onigiri were to weak and would easily get killed, Sano comments that they were really more like chickens then "pigs" but
Buccha states they should continue otherwise everything that has happened might end up being worthless. They all proceed forward and Aeon admires both Buccha and Onigiri as storm riders. As they continue going forward Agito later "disapears" leaving Sano to deduct that the enemy is trying to split them all up. Sano, Buccha, and Onigiri move on separately into three hatches and tells them both they will definitely meet again. Sano is later seen striking down Alexander Locke from behind easily defeating him, although whether he kills him or spares his life is not known. Thinking back to what Buccha and Onigiri said, he chooses to go back for Kazu.
Aeon clock is currently looking for Kazu, it was revealed in chapter 287 that he put hidden cameras all over "Colonel Sanders" to watch all the battles that were going on. Sano becomes irritated when he found out that the Storm Regalia was damaged, and he later calls Ikki on his cell phone giving him an update of everything that's happened.
As of now, after 's locatiKazuon, Aeon and Kazu are both battling Nike in Onigiri's place. Kazu had a flashback to a time when virtual Spitfire was teaching him. According to Spitfire, the Gem road is the worst opponent for the Flame road. He taught Kazu plans A to F, which would all end up in "Death" according to Aeon. Kazu chose Plan B in which he held Nike, who was in turn attacked by Aeon. Nike had a look of surprise as Aeon broke through his defenses and revealed his "All Purpose" Regalia called Phantom which he had Taeko build into his own body. Not much has been revealed about this Regalia, but it is assumed that it can use all roads as Aeon was using the Thorn road when he managed to hit Nike. Most likely, it is a perfected version of Taeko's Regalia. After Aeon makes his company sing about how his new cyborg body is the fruit of their technological achievements, he breaks through Nike's "Gem" barrier by combining the Thorn and Thunder Roads. This provides the opening for Aeon and Kazu's St. Elmo's
Crossfire. The cross of flames had little effect on Nike, who revealed his "Gem" form - an augmentation of his body. He was then attacked by Onigiri, who revealed that the Crossfire was only one part of the attack - mixed with the pig's nitrogen, it filled the gap in Nike's heart that the Crossfire created and allowed an explosion from the inside out. The attack did some level of damage to Nike, however Nike releases his ace, which is two blades connected to his legs and reverses the attack causing Aeon's regalia to be ripped out of his body. He loses the ability to battle, and tunes the Flame Regalia using "Phantom". He gives the regalia to Kazu, telling him that it wouldn't be long until he leaves it in his hands, and how exciting it was watching him grow from an inexperienced kid to a Storm Rider deserving the title of the Flame King. Aeon dies after saying his last words, being sliced in half by Nike.
Sano serves as Simca's advisor, counselor, and occasional chauffeur. She recruited him as a member of Genesis and they are close friends.
He is loyal to Ikki and his primary role in Genesis is to protect and aid him. Later he confesses his love for him.
He is shown to have a rivalry with Spitfire as he once desired to become the Flame King, but aside from that they seem to be on good terms and have mutual respect for each other. When he and Spitfire were on the same team, Spitfire taught him tricks such as using light to become unseen. Despite his rivalry with Spitfire, he immediately came to his aid during the fight against the Takeuchi brothers, even trading jokes and insults with him.
Mimasaka Ryo is a close friend of Yasuyoshi Sano. They've known each other since their school days. It's clear that she holds a large place in his heart, as he is visibly furious at the Takeuchi brothers after she is apparently killed, which is contrary to his usually calm and rational demeanor. They were also both members of Behemoth. He is currently working under Genesis, who is holding a comatose Ryo hostage, and intends to revive her.
Sano is an A-Class Storm Rider who follows the Flame Road. He specializes almost exclusively in the "Time" technique, having developed numerous offshoot tricks. During his time with Behemoth his R.E.A.D level was 82. Like Benkei, he is not a King, but has repeatedly displayed the ability to fight on par with one. It is unclear how severely his battle with Sora and Nike has impeded his fighting skills; he is clearly unable to keep up with the strength and speed of Noyamono Mikan's Gale Road, but he was able to take Genesis' Flame King by surprise with his speed. During the battle with Nike, it is revealed that his current battle level has risen to 306. His speed has also been shown to increased tremendously compared to before.
Sano has been seen using both traditional ATs and the special "Ball Roller" type.Since joining Genesis, he has relied exclusively on the latter type, sacrificing numerous functions for enhanced maneuverability. But now as he has got his hands on the Flame Regalia he wears them.
Time - Sano's signature technique. His mastery of this ability earned him the nickname Aeon Clock. The first technique of this name manipulates light to bend around Aeon using heat, rendering him invisible to give the illusion of controlling time. The second technique Aeon uses causes an "over rev" phenomenon, where the victim's brain is using it's resources solely to process vision, and cannot respond to an imminent strike.
Reincarnation - Sano's strongest Time variation. After "stopping time", he executes a spin to get underneath his opponent and then transfers all of the resulting momentum into them, sending them flying. Said to be the strongest of Sanos 48 attacks.
Time Reversal - Sano named this technique as one of his Time offshoots during the celebration of Ikki's release from the hospital. It consists of him simply projectile vomiting, making it a gag technique.
Time Shield - Like Kazu, Sano has been seen using the Time technique to shield against enemy attacks. He is first seen using it against Mikan Noyamono's assault, although it is not strong enough to hold her back completely.
Flames of Time - This technique implements more Flame Road principles into Sano's Time tricks. With it, he can fire numerous blasts of energy at his enemies, inflicting serious damage. He first uses it against Gabishi during their skirmish, and again in tandem with Spitfire during their fight against the Takeuchi brothers.
Time Mirror - Sano utilized this technique to briefly counter Nike's regalia. By using his speed to kick the ground extremely rapidly, he applied the same paralysis effect caused by the Gem Regalia to Nike, giving Spitfire a chance to give the Flame Regalia to Kazu.
Giant Swing of Time - After using Oh ! Time, Sano plants a hand on the ground and swings his feet like a pendulum. He is only seen using this ability once: against Kazu during the Behemoth match.
St. Elmo's Crossfire - By teaming up with Spitfire, Sano was able to use this technique against Nike. It creates a cross-shaped blaze that sends the targeted enemy flying into the ground. Although Nike used his Jade Road to escape harm, it is presumably a very powerful technique.
Cloak of Time - Makes the user and or who the user want be made invisible for a short period of time.
In the last chapter, Spitfire jokes that Sano had actually died alongside him in the battle against Sora and Nike, and the one fighting on the aircraft carrier was a remotely-controlled robot.