Liin comes from a very long line of guardians who have sworn to protect the Eternal Ice with their lives. When he came of age, he was trained by his father to become a master of the ice arts. After his training was finished, he was sent through the clan's Trial of Guardianship. He braved the dangers within, and was made guardian of the Eternal Ice, and his father, the previous guardian, stepped down.
Liin was quite detached from the Armageddon Event for most of it's run. However, when Striker the Hedgehog managed to get past Darshina's guardian, Jayhan Bostayn, he was forced to do battle with Striker himself. His prowess with ice manipulation overwhelmed Striker's speed and agility, and Striker was forced to flee, never to go after the Eternal Ice again.
Guardians of Earth Era
Not much has changed with Liin after the Armageddon Event had passed. He stayed and guarded the Eternal Ice, just as he had always done. But eventually the Transk Tyranny, led by Dr. Garcandin Transk, began going for the Ice, and, thanks to the warning from Shawn the Hedgehog and Lisa the Hedgehog, he readied the mountains for combat. With help from several others, including world-renowned hero Sonic the Hedgehog, he had beaten back the Tyranny and kept the Eternal Ice safe.
Ice defines Liin's outward personality very well; He often gives the feeling of being cold and emotionless. However, on the inside, he has a lot to say, including various sarcastic remarks, or even pointing out something inconsistent, all of which he does in his head.
Liin is a master of his clan's traditional art of ice manipulation, rivaling Sonic's (and therefore Striker's) speed with his expertise of ice, including flash-freezing their feet to the ground should the need arise. He is also proficient with spin attacks and tail slashes. If he ever needs to leave the Liinan Mountains for any reason, he can flash-freeze an ice path to travel on, gaining sliding momentum if he needs to go higher, or just making stairs.
Liin is vulnerable to fire-based attacks, which weaken his power over ice, as well as being potentially fatal. Similarly, extreme heat weakens his abilities, meaning he may require a refrigerated suit to be able to protect himself in such environments.