Kirito is the protagonist of Sword Art Online. Although he initially started out being a loner and often avoided working in groups during the series, he also eventually gained friends along the way, as well as romantic bonds with characters such as Asuna.
However, there are some characters from other anime that could probably bond with Kirito, despite his initial loner-centric personality. From Gon's determined personality to Azusa's magical assistance, these anime characters could either stand by his side in battle or be greatly supportive of their helpful presence. Not only would they be helpful, but they have personalities that would work well with Kirito's own.
10 Gon Would Prove To Be A Great Ally To Kirito Due To His Adaptability And Kindness (Hunter X Hunter)
Gon from Hunter X Hunter would be a great friend for Kirito to have in the long run. Gon is fairly optimistic and kind, but he's also an adaptable and good fighter. He would help lighten up the situation as needed and also help keep morality high. Additionally, much like Kirito, Gon himself is a determined individual. No matter how tough the battle is ahead of him, he won't give up.
9 Nami Will Work Well With Kirito, Assuming They Don't End Up In A Situation Against Each Other (One Piece)
Nami from One Piece is a fairly practical person and an expert when it comes to stealth and thievery. This could potentially make her clash with Kirito, but it could also be helpful if the two of them worked together. She and Kirito could be a practical but fun pair when they're not in battle, and they would enjoy hanging out with each other whenever they're not fighting any enemies or getting out of troublesome situations.
8 Reiji Would Be The Perfect Go-To Friend For Any Medical Assistance (Drugstore In Another World)
Reiji from Drugstore In Another World is a pharmacist, so he could easily whip up potions to help out Kirito when the situation gets rough. Considering Reiji's specialization in medical knowledge, it wouldn't be wise to bring him into battle.
Just because Reiji isn't a fighter doesn't mean he's not useful, though. His potions could probably help save Kirito's life and the lives of his other friends. This could be handy in a pinch when facing any particularly tough foes.
7 Aiz Wallenstein Would Be A Great Fighter By Kirito's Side (Is It Wrong To Try To Pick Up Girls In A Dungeon!?)
Aiz Wallenstein is one of the strongest members of the Loki Familia in Is It Wrong To Try To Pick Up Girls In A Dungeon!? Her vast battle skills would make her a great ally in battle, as well as an awesome sparring partner. Considering that she was skilled enough to train Bell, the protagonist of the series, she could also help Kirito learn a few things about swordplay. Both of them fighting together would make them near-unstoppable, especially against the incredibly powerful enemies they face in their respective series.
6 Sailor Mercury's Intelligence Would Be A Boon To Kirito In And Out Of Battle (Sailor Moon)
Whenever Kirito has to investigate a new area or enemy, it would be great if Sailor Mercury was by his side. She could use her Mercury Glasses to quickly identify enemies' weak spots, and also check if there are any threatening foes in the new areas she and Kirito explore together. Considering how she is a fairly intelligent Sailor Scout, she and Kirito would be able to work together to solve any huge mystery if they put their brains together.
5 Shin's Powerful Magic Could Help Kirito, And Kirito Could Help Him With Common Sense (Kenja No Mago)
Shin from the manga and anime Kenja No Mago, also known as Wise Man's Grandchild, is an extremely powerful magic user. However, he severely lacks common sense, which could make him enemies quicker than friends.
If he worked with Kirito, Kirito could help him get some common sense while Shin helps him train further in using magic, seeing that he has a vast intelligence in that area. The partnership would be a fun one between the two despite potential hijinks involving a lack of common sense.
4 Azusa Would Be A Great Overpowered Friend (I've Been Killing Slimes For 300 Years And Maxed Out My Level)
Azusa is another incredibly powerful magic user that would be a great ally to Kirito, and also one of the strongest characters from her series. She arguably could be even more powerful than Kirito, considering that she has had three hundred years to level up. She can even create her own spells, which could help Kirito out if there are any unique situations that normal magic can't fix.
3 Sadao Maou Is The Literal Devil, But He's A Nice Person (The Devil Is A Part-Timer!)
Despite being the literal Satan, Sadao Maou is actually a nice person. This, coupled with his powerful abilities, would make him easy for Kirito to work with.
Also, Maou would be able to empathize with Kirito when it comes to being stuck in an alternate world, considering that he had to figure out living in Japan after he was sent out of Ente Isla. Both of them would be able to bond with each other over this, on top of being great allies to each other in battle.
2 Aletta Would Be Happy To Serve Food (Restaurant To Another World)
Aletta from Restaurant To Another World would be a helpful ally and friend. Though she likely could not be much of a help in battle, she could still whip up and serve some tasty dishes. If Kirito ever visited the Nekoya Restaurant, he and Aletta could become quick friends over food. Her presence would help him forget about all the fighting he has to do for a little while. Additionally, if Aletta ever got into danger, Kirito could help her out in those times of need.
1 Kai Suwabara Would Be A Helpful Swordsman By His Side (Yakitate!! Japan)
Kai Suwabara from Yakitate!! Japan would be a serious, but helpful ally. He might be a baker, but he's also extremely proficient with a sword. Him and Kirito working together would make them a hard-to-beat pair of anime swordsmen, and then they could just bake bread and eat it afterward to take a break from all the stressful fighting. Both of them are also fairly smart characters, too. If they get stuck in a tricky situation, they could work together to solve it.