Calem is a young boy who was born in Hoenn, and lived there for the first 18 years of his life. He decided to remain in school for all of his teenage life, opposed to starting his adventure at age 10. He planned to go on an adventure in Hoenn once he finished, however, his family decided to move just as he was going to do so, leading him to move to Kalos with them. When they had settled in Vaniville Town, he decided to go on his adventure.
- Xenial Destiny I
Calem first appeared in Welcome to Kalos! A New Adventure Awaits! when he met Lexi after being informed of her arrival by Professor Sycamore. He and Shauna brought her to Aquacorde Town where all three of them received a Pokédex and their starter Pokémon alongside other kids Tierno and Trevor, in which he received a Froakie. They all joined together to head through Santalune Forest, in which Tierno and Trevor had gotten lost. Despite going back to help them, Calem's cocky nature resulted in them all getting in further danger, until Lexi saved them all. After venturing through the forest and saying bye to Tierno and Trevor, Calem headed to Santalune City with Lexi and Shauna. While there, Calem battled in a tag battle with Lexi against sisters: journalist Alexa and Santalune City Gym Leader Viola. Calem and Lexi won after Alexa threw the match, which ultimately led to Lexi and Viola's Gym battle. When Calem decided to battle Viola, she handed him a Gym Badge anyway after their tag battle, ultimately giving Calem his first Gym badge.
Calem joined Lexi on a long-time basis on her journey after deciding that he can learn to be more humble and become a better Trainer while with her. After the group entered Parterre Way, Calem wanted to capture a Pokémon that stayed by his side outside of its Pokéball like Lexi's Helioptile and Fennekin; which ultimately led to the capture of Skiddo.
As time progressed, Calem began to feel ousted from the trio, with Lexi and new companion Valerie (who joined after Lumiose City) often mocking or belittling him. After having a conversation with several members of Team Flare and Lysandre, in The Last Straw, he stormed off from Lexi and ultimately, became a member of Team Flare.
Throughout Invasion, Calem was seen usually with Lysandre, where he began training him to become a better Trainer and battler. He challenged Valerie to a Gym Battle in An Unfriendly Gym Battle in which he won his next Gym badge. He then challenged Lexi to a battle in The Demanding Call!, in which the two exchanged harsh words towards each other.
When Team Flare formally announced their plans to detonate the Ultimate Weapon and Lysandre was revealed as Leader, Calem was seen helping the team with their plans. He and Lexi battled once more in Calem's Revenge!.
As Team Flare's plans intensified, when the battle between Team Flare and Lexi and her friends resulted in Tierno's death, Calem turned his back on Lysandre and Team Flare vowing to get revenge. He then aided Lexi in taking down Lysandre and faced off against Xerneas.
Calem appeared alongside Shauna in A Bond & the Letter, in which it was revealed that he was defeated in his third battle against Siebold for the Kalos Champion title. It was also revealed that he and Shauna were heading to Hoenn together for the next leg of their journey's. Calem also finally admitted his feeling for Lexi, however, when he turned her down and turned down the offer to head to Hoenn with them, he left with Shauna, but not before kissing Lexi.
Calem reappeared in X vs. Y: Destruction to battle in the war. He was apart of the team when they headed into Lumiose City, and eventually when the war officially begins. He ran into the burning building which captivated Lexi and Lysandre along with Marlon, in which he successfully finds Lexi. However, he is unable to save her as she releases her hand, but not before she kissed him back.
- Xenial Destiny II
Calem appeared again in Ruby & Sapphire alongside Shauna and Marlon on their Hoenn adventure. Calem had gathered all but 3 of his Gym Badges from Hoenn; in this time he changed his appearance and became a much more mature and focused battler.
He appeared in Spotlight! Introducing Lisia! when he was seen beating Roxanne at her Gym where he revealed his plans to go to Mauville City. In Taking a New Path, the trio are joined by Roxanne and it's discovered after Roxanne mentions a Trainer named Lexi that Calem was still deeply troubled by her death.
He was seen again in Destinies Align! when he was seen battling against Wattson by May. In Lights On! May vs. Wattson! he is once again reminded of Lexi after Roxanne shows them a picture of her and the Trainer she was searching for, although Calem admits that it would be impossible to be her.
It appeared that after battling at Mauville City he and the others did indeed go to Fallarbor Town for Shauna's Contest, and upon traveling back to Mauville they discovered the issues at Mt. Chimney in Race of Mt. Chimney!. In A Volcanic Showdown!, Calem and the others arrive at Mt. Chimney and help the group stop the destruction of the landmark, before he discovers Lexi is alive and well.
In Aftershock! Calem is shown to be deeply hurt and angry after discovering her to be alive, refusing to speak to her. He eventually does so and confronts her about whether or not the things she did and said at Parfum Palace where true which she tells him they were. He then reluctantly agreed to journey with Lexi alongside May, Brendan, Shauna and Marlon, claiming he was only doing it for Shauna and Marlon. In Keeping Promises!, he and Lexi make their peace for the sake of the group.
From then on, Calem grew closer to Lexi again as he traveled with them. He was shown to have grown much stronger and even given a Mega Ring from Steven and offered a chance to be a Mega Apprentice, much to his happiness. After successfully aiding in stopping Team Magma and Team Aqua, along with the threats of Groudon, Kyogre and Deoxys, he, alongside Shauna, begun their training with Steven to become Mega Masters. He decided to remain in Hoenn to continue his training when Lexi revealed her plans to leave for a new journey. Despite remaining, he told her that she wouldn't have a chance to miss him, as as soon as he completes his training, he'd find her and join her once more.
Calem returned in the Gallant Fate series. Having completed the Mark of Mastery Exam, Calem headed to Galar with Marlon to meet his family. However, he ended up running into Lexi and her at that point uncontrolled Type: Null, resulting in the group reuniting.
Calem's intention in Galar is to use his new found strength and knowledge to become Champion of Galar, finding out from Nessa how big of an event the Gym Challenge is within the region. He decided to join Lexi for the purpose of learning from her, and training with her. He also decided to not rely on his Mega Evolution capabilities, and wanted to create a whole new team of Galarian Pokémon.
Calem is a confidant for Lexi throughout the journey, while facing his insecurities of his own skills. He manages to excel however, making it to the Semi-Finals of the Champion Cup, only to be beat by Nessa.