Okay, so this isnt the full list but its what i have to post atm so it can be discussed in the meantime. will post the rest later, but these are all people that Aatrox is canonically significantly more skilled than:
Yasuo is the only swordsman in a century who was able to master the Wind Technique, which is a sword style that works by making cuts and thrusts so precise with your sword that you directly manipulate wind currents to the point of being able to create tornadoes with a swing of your sword, and despite being completely nonmagical it is indistinguishable from actual magic. Yasuo is more skilled than Master Yi, who has dozens of years of experience in the art of Wuju, and even before Yi mastered Wuju he was considered one of the most skilled practitioners of the martial art. Wuju Style requires an immense amount of patience and strategy, centered around analyzing the opponent for any openings or weaknesses before killing them with a single cut. Yi has been described as never attacking until landing a strike on his opponent was absolutely guaranteed. Master Yi is more skilled than Lee Sin, a master of all of Ionia's martial arts who is able to fight completely blind just by using his hearing, and just by listening to the movement and breathing of three men was able to determine that one had the early symptoms of lung disease, one had a weak heart that would give out in less than a year, and one had an injured spine that forced him to walk slightly more on his left side.
Lee Sin is more skilled than Shen, a master ninja who has been trained since childhood in the art of ninjutsu in and combat analysis in order to take up the mantle of the Eye of Twilight. Everything that his students Akali and Kennen can do, he can do better, as well as having the ability to automatically react to attacks due to his energy in the spirit realm protecting his body in the physical realm by automatically making him dodge even if he isnt aware of an incoming attack. His skill in combat analysis is such that, while in a crowded, busy ballroom, Shen was able to instantly deduce that his target was half a finger length too far way for him to be able to attack the moment he saw him, despite the latter being in a disguise and a master of stealth attempting to avoid detection.
Shen is more skilled than Akali, a master assassin, having been trained to kill since the moment she was able to walk. Having been personally trained to use shurikens by Kennen, personally trained in the ninja arts, stealth, and subterfuge by Shen, as well as developing her own fighting style of emphasizing speed and agility over strength and becoming a master of the kama and kunai. Her skill is so great that she succeeded her mother as the Fist of Shadow when she was only a teenager, and despite not possessing any innate supernatural abilities like Shen and Kennen she was considered just as deadly as them. She has knowledge of over 300 pressure points on the human body and how to exploit all of them, and can do so offhandedly from across a room that is obscured with a thick smokescreen.
Akali is more skilled than Xin Zhao, a master spear wielder, world renowned for having never lost a one-on-one fight in his life. Hyper-analytical and hyper-observant, even at an early age his skill with a spear was quickly noticed by the Noxian commander who owned him, earning him a spot as a Reckoner due to his martial prowess and rapidly elevating him to fame in gladiatorial combat. On the battlefield Xin Zhao's skill only shined brighter, having singlehandedly killed several hundred Demacian soldiers and only being halted by an entire battalion of the Dauntless Vanguard engaging him all at once, with many of the members of the Vanguard were silently impressed by his skill. He is also highly skilled in hand to hand combat, having disarmed and incapacitated two of King Jarvan III's personal guard, who by his own admission had undergone decades of brutal training to reach their positions, as well as Sword Captain Tianna Crownguard, the leader of the Dauntless Vanguard, as a demonstration of his skill. After becoming Jarvan III's seneschal he achieved feats such as fighting through an army of Freljordian warriors several hundred strong with only Jarvan III as backup and mastering wielding Drakebane, an ancient lance so lethal to wield that in unskilled hands it was as deadly to its wielder as to the enemy, with no prior knowledge of how to wield it as the secrets of how to fight with it had been lost for centuries, and later going on to train Jarvan IV to wield it at a master level. He has also shown a high level of proficiency in dual wielding, able to casually avoid and parry the attacks of an enraged Jarvan IV while wielding a spear and a dulled training sword.
Xin Zhao is more skilled than Jarvan IV, a highly intelligent individual, having been given the finest Demacian education available since he was a child, learning from Demacia's finest historical scholars and tutored in the ways of ruling a kingdom, as well as being personally tutored in the history and politics of Valoran by Xin Zhao, who also taught him about the world’s more spiritual philosophies, as well as the myriad arts of war. He is skilled with a variety of weapons, though his preferred is his lance Drakebane, an ancient lance so lethal to wield that in unskilled hands it was as deadly to its wielder as to the enemy, which he wields with the skill of a master, with even Xin Zhao, his mentor who taught him everything he knew about how to wield the lance in the first place and who had been training in the use of pole-arms and other similar weaponry and who learned how to wield Drakebane from scratch, acknowledging that Jarvan's skill with the weapon far exceeded his own. At the age of 18 Jarvan was awarded the honorary rank of general, leading him to pursue a career on the battlefield, securing numerous victories and quickly growing a respectable reputation as a general, leading from the front lines and able to rally his troops even against impossible odds, such as his small, exhausted, and injured battalion which had barely survived a Noxian ambush going on to help Shyvana kill her mother, a fire elemental dragon.
Jarvan is more skilled than Garen, a highly skilled combatant and strategist, widely considered to be one of the greatest swordsmen in Demacia, having trained non-stop from the age of twelve in the art of combat and war and quickly gaining a fearsome reputation on the battlefield. By the time he turned eighteen he had already served in multiple campaigns, fighting off Freljordian barbarians, mages, and the Noxian military, which granted him a nomination as a member of the Dauntless Vanguard, a position he won with ease through his sheer courage and skill. His skill was so well recognized by the rest of the Vanguard that of the over two thousand members [each being a legendary hero in their own right, the most skilled and well trained soldiers in Demacia, masters of multiple weapons, and boasting extensive knowledge of battle tactics and warfare on top of having accomplished extraordinary feats such as singlehandedly slaying dragons and wyrms, outmatching entire hosts of the Trifarian Legion, and being able to take on entire armies on their own and emerge victorious] he was chosen to be the new Sword-Captain after the previous leader had died, a decision that was unopposed by any member of the Vanguard. As a member of the Dauntless Vanguard, Garen is a master of battlefield strategy, able to communicate entire combat plans to other members of the Vanguard through nothing but subtle eye and facial movements, as well as perceive other members' strategies given in the same manner through just peripheral vision, and doing so at a speed described as blindingly fast by people less trained than them. He is also hyper-observant, as all members of the Vanguard are required to master the art of observation of every aspect of the battlefield as well as potential changes that could be made both within and outside of their line of sight at any given moment and identify what their enemy is observing and how they can potentially advance.
Garen is more skilled than the Trifarian Legion, the elite Noxian military force and the most prestigious warriors the empire could produce, and that hold a reputation known throughout Valoran, even among those who had never fought beside or against them, and are so feared that just two legionaries could take over an entire city. Each member of the Legion is personally trained by Darius, a highly skilled military strategist and combatant whose his fearsome notoriety is so widely recognized even in the lands beyond Noxus that it is not uncommon for entire cities to surrender at the first sight of his banners. Having served in the Noxian warhost since he was 12, Darius has spent most of his life fighting in numerous grueling campaigns of conquest from one end of the known world to the other, as well as crushing a number of rebellions against the throne. As he rose steadily through the ranks he garnered a great respect for his aggression, discipline, and refusal to ever take a backward step, even going so far as beheading a Noxian general after he ordered a retreat, rallying the scattered warbands and winning a great and unexpected victory against a far more numerous foe.