Kirito isn’t a traditional Chosen One like Harry Potter but rather a Neo character. Someone who comes across on the surface as ordinary but holds great potential. No one could have foreseen how he would be natural at the game of SAO, not even the creator. When 10,000 people get trapped in the game and have to fight for their life, it’s here where Kirito’s gift becomes extraordinary and he steps into the role as the savior or Chosen One of his story.
The entire arc of SAO builds Kirito to the point where he could no longer die. In the fight against The Gleam Eyes, we see Kirito nearly single handedly defeat the monster with his unique skill, dual wielding. The dual wielding skill is given to the player with the fastest reaction time. It is later revealed during the final battle the dual wielding skill was designed for the player intended to stand against the final boss. It is clear here that Kirito is in fact the chosen one.
In the game, Kirito spends most of his time as a solo player. Eventually Kirito places a bet on his freedom in a fight against Heathcliff the leader of the Knights of the Blood Oath guild. Heathcliff has his own unique skill in the game called the Divine Blade which allows the player to switch between offense and defense freely granting nearly impenetrable defense. After a hard-fought battle Kirito is defeated and forced to join Heathcliff’s side. After a series of events Kirito realizes that Heathcliff isn’t who he says he is. It is revealed that Heathcliff is actually the creator of SAO, Kayaba Akihiko. He gives Kirito the choice to fight him right then and there or wait for him at the final level of the game. Kirito chooses to fight for everyone knowing it’s there’s a chance he wins and frees everyone from the prison that is SAO. Kayaba has the obvious advantage being the creator of SAO and knowing all of Kirito’s skills having designed them. He fights as hard as he can and is almost killed before his girlfriend Asuna jumps in the way of Kayaba’s final strike sacrificing herself for Kirito. As she dies in Kirito’s arms, he loses his spirit to fight. We see what we think is the final blow as Kayaba impales Kirito with his sword, and there seems to be no hope. Just as Kirito’s HP bar drops to 0 we see him defy death and do the impossible, picking up his sword, killing Kayaba and winning SAO saving everyone who was still alive and Asuna.
In that moment we see Kirito’s eyes turn from a grayish black to golden yellow.This is not the only case that we see Kirito’s eyes turn yellow. We also see his eyes change in ALO when he is raiding the World Tree, which I will touch on later, and in GGO when he is about to die in his fight against Death Gun. The Yellow eyes appear at moments in the show where Kirito is about to die or does the impossible. Not much info is given on why this happens, but it seems that it is Kirito’s will power giving him the ability to do the impossible as the Chosen One or Hero of the story.
After Kirito wins SAO a number of players are still trapped inside the system including his girlfriend Asuna. He finds out that Asuna is trapped at the top of the World Tree in the game ALO, a tree that no one has ever been able to climb. Kirito is the first to get to the top of the tree where he fights the main antagonist who is holding Asuna prisoner. Kirito is able to defeat the antagonist by gaining access to Kayaba’s old account. After saving Asuna and helping her escape, Kirito meets Kayaba who gives him the World Seed. The World Seed is the building blocks to new virtual reality worlds. The story was inevitably building up to this moment and how he later builds Accel World which is the culmination of his destiny as the savior.