"Kitsune. But 'Fox' works, too."
— Liam and Kira after Liam's introduction to the supernatural in The Benefactor
The two met in Season 4, after Liam transferred to Beacon Hills High School from Devenford Prep and joined the lacrosse team there, a team that Kira was ultimately invited to join as well as a result of her superhuman agility impressing Coach Finstock.
After Liam was inadvertently bitten and turned into a Beta Werewolf by Scott McCall, Kira's then-boyfriend and the Alpha of their pack, Kira joined the rest of her friends in staging a supernatural "intervention" at the Martin Family lake house; Kira lured him to the lake house under the guise of asking him on a date to a party allegedly being thrown there. Once they arrived, Liam was not impressed when Kira's decision locked him inside the house with the rest of the pack to reveal the existence of the supernatural world to him, and he seemed skeptical when he learned that Kira was a Thunder Kitsune, a supernatural fox spirit.
Fortunately for them, Liam came to believe what they said was true after his first transformation during the full moon and began developing relationships with Kira and the rest of the McCall Pack. Kira and Liam, as two of the four shapeshifters in the pack, grew to trust each other implicitly and defended each other against all threats, such as the arrival of the Werejaguar Kate Argent and her Berserkers to Beacon Hills and the ongoing Deadpool hit-list of supernatural creatures underway in the town.
Their friendship continued on throughout Season 5, and even though Kira has since moved to Shiprock, New Mexico full time to train with the Skinwalkers there, the two remain friends, with Liam even approaching Kira's mother, Noshiko Yukimura, to gain her help in fighting the Ghost Riders of the Wild Hunt by using Kira's magical katana, though Liam was forced to break the sword in order to gain Theo Raeken's help.
Kira and Liam are referred to as Lira (and, less commonly, Kiriam or Yunbar) by fans.
Throughout Teen Wolf
In Muted, Kira watched the Beacon Hills Cyclones lacrosse practice with Malia, where she witnessed Liam's prodigious skill at the sport and was eventually offered a place on the team as well due to her quick reflexes.
In The Benefactor, after Scott bit Liam, the pack planned to use Kira to lure Liam to the Martin Lake House by claiming that Lydia was throwing a party, though in reality, they intended to help him get through his first full moon whether he wanted their help or not. Liam began to experience the effects of the full moon while Kira was driving them to the lake house, and they briefly discussed Lydia's family and the party as Liam's sense of hearing became stronger and more heightened. Upon their arrival, Liam began to realize that things were not as they seemed when only a few cars were parked out front, and by the time they entered the lake house, it became clear that Kira had lied to Liam to get him there when he found Scott, Stiles, Lydia, and Malia waiting for them.
After the others briefly explained their identities as a Werewolf, a Werecoyote, and a Banshee, Liam mistakenly referred to Kira as a "Fox" before Kira replied that she is a Kitsune, though she assured him that Fox wasn't an incorrect term. Kira became alarmed when Liam made it clear that he thought they were all crazy, but after the moon rose and Liam began to transform, Scott and Kira rushed Liam out into the boathouse to chain him up. When Scott, who felt guilty for turning Liam against his will in the first place, found himself incapable of restraining Liam without harming him, Liam tackled him and was about to maul him when Kira, at a loss for options, hit Liam upside the head with a boat oar and knocked him out, allowing them to chain him to a support beam. While Liam was unconscious, Kira brought up how young Liam was at just fifteen years old and asked Scott what they would do if Liam didn't want their help, but Scott assured her that he eventually would, remembering his own experience as a newly-turned Beta. While Scott and Kira were slow-dancing on the dock, Liam started to wake up, and his full-moon-enhanced powers combined with his anger and confusion made him strong enough to easily break through the chains and jump through the nearby window, forcing Scott to chase after him while Kira ran inside for help.
In I.E.D. Liam and Kira both played in their first game after joining the Beacon Hills High School lacrosse team, and the two of them, along with Scott and Stiles, were on high alert for Garrett to attack them due to their names being on the Deadpool hit-list. Liam was standing with Kira on the sidelines when it was revealed that the second portion of the hit-list had been decrypted and that Kira's mother Noshiko was on it. After Kira left to inform her mother, Liam went to find Scott to tell him that Kira left.
In Time of Death, Liam and Kira fought Kate's Berserker in the hospital, which easily overpowered them both at first until Kate called them off. Kira was knocked unconscious for a brief moment, but Liam woke her up to save her from being hurt further. When Liam was knocked onto the ground, Kira continued to fight the Berserker and insisted that he run for safety, but Liam wouldn't give up on her and instead jumped on a transformer tower to more easily tackle it. After Scott was awakened and Kate and her Berserkers left, Liam caught up with Kira and regretfully informed her that her mother, Noshiko, had been attacked by one of the Berserkers before they left.
In Smoke and Mirrors, Liam insisted on going with Stiles, Malia, Derek, Braeden, and Peter to go save Kira and Scott from Kate, despite the fact that he had only been a werewolf for a short time and there was a full moon that night. Liam was locked up by Derek and Stiles in the back of a prison transport van that Braeden was driving while the two tried to teach him to control his shift, which was ultimately successful despite Liam breaking out of his cuffs and nearly mauling Derek. Upon arriving at La Iglesia, Liam, Malia, and Peter fought a Berserker and nearly killed it until Kira appeared with Stiles and informed them that the Berserker they were fighting was Scott, who had been turned by Kate the previous night. Kira and Liam, along with Stiles, tried to get Scott to recognize them, and though Scott knocked both Kira and Stiles onto the ground and nearly choked Liam to death, Liam was able to remind him that he was a werewolf so he could turn himself back.
In Creatures of the Night, Liam asked Scott and Stiles why Kira, Malia and Lydia weren't with them that night, but Stiles told Liam that the girls planned to meet them at the high school for Senior Scribe, though he refused to tell Liam any details about what was going on. After Liam overheard Jordan Parrish, Melissa McCall, and Sheriff Stilinski talking about a mysterious new shapeshifter named Belasko who was going after Scott, Liam rushed to the high school to inform Stiles and Malia before the three rushed to save Kira and Scott from him.
In Dreamcatchers, Liam looked slightly embarrassed when his best friend Mason expressed his glee about the supernatural while the McCall Pack planned their next move in dealing with Tracy Stewart, especially when Mason pointed out that Kira, as a Kitsune, was something he didn't understand.
In Condition Terminal, after Kira and Scott learned that a dangerous Werewolf-Scorpion Chimera named Lucas was at Sinema, where they knew Liam and Mason were hanging out, they rushed to the club to find Liam already fighting Lucas. After Liam managed to knock Liam unconscious, he and Scott both looked horrified when Kira's Kitsune spirit took over and nearly cut Lucas' head off with her katana until Scott stopped her.
In Ouroboros, Kira expressed her desire to help Scott find Liam and Hayden after they had been captured by the Dread Doctors, but because her out-of-control Kitsune spirit had caused her to unintentionally kill an unnamed female Chimera, she was unable to do so, and eventually decided to leave town to figure out how to control her inner Fox.
In Codominance, Liam, while trying to reconcile with Scott after the events of Status Asthmaticus, eagerly volunteered to go with him and Stiles to go find Kira in Shiprock, New Mexico and bring her back, but Scott, still dealing with Liam's attempt to kill him, declined his offer and left him behind in Beacon Hills.
In Amplification, Kira and Liam were both present at the pack meeting at the McCall House to discuss how they would be breaking Lydia out of Eichen House, and both seemed very nervous about the number of aspects that could go wrong. Later that day, when Kira admitted to the others that she had failed all of her practice tries at siphoning enough electricity with her Kitsune powers to cause a brownout, Liam was the first person, after Scott, to voice his assurance that Kira could do it. That night, when the brownout occurred, Liam excitedly exclaimed his happiness that Kira was able to control her powers enough to not cause a lockdown.
In A Credible Threat, Liam and Kira, along with Scott and Stiles, played in the charity lacrosse game against Devenford Prep. When it became clear that Kira's Kitsune spirit had taken control of her and was causing her to act aggressively toward the players of both teams, Liam asked Scott if it was time to go to the backup plan. When Scott agreed that they needed to do it, Liam informed Brett Talbot of what was going on and requested that he tackle Kira to bait her into attacking him and getting kicked out of the game.
In The Beast of Beacon Hills, Kira and Liam joined Stiles, Malia, and Lydia in the McCall House kitchen while they waited for Scott to awaken and find out whether or not he had healed from his battle with the Beast. Once Scott awakened, they all discussed their plan to save Mason from being consumed by Sebastien Valet's spirit.
In Apotheosis, Kira and Liam reunited for the final battle when Kira and Lydia arrived to find Scott and Liam fighting Sebastien/the Beast. After Lydia used her Banshee voice to shout Mason's name, Sebastien turned back into Mason, allowing Scott to kill the Beast. When Theo arrived and prepared to use his newly-gained electromagnetokinesis to electrocute Scott and Liam, Kira jumped in front of them and summoned the electricity into her sword before plunging the blade into the ground to create a sinkhole that swallowed Theo whole and trapped him underneath the tunnels.
- Kira and Liam are both on the Beacon Hills lacrosse team, with Kira playing as #15 and Liam playing as #9.
- Kira and Liam are both very close with their Alpha, Scott, with whom they each have very special relationships. Scott and Kira have a romantic and sexual relationship, whereas Scott and Liam have an Alpha/Beta friendship, since Liam was the first person to whom Scott ever gave the Bite and turned into a werewolf.