First Lieutenant Lin is the second-in-command character of the 12th Battalion and one of the main protagonists of the video game Advance Wars: Days of Ruin.
Lin first found Will along with Brenner while Will was being attacked by The Beast's Bandit Raiders. After fighting off the raiders, Lin and Brenner accepted Will into the ranks of the 12th Battalion.
After Brenner was killed by Admiral Greyfield in revenge for him saving the captured Lazurian troops from being executed by the New Rubinelle Army, Lin appointed Will as the new leader of Brenner's Wolves, despite her being the second-in-command, due to her hoping that Will being leader would lessen the tensions between the Rubinelle and Lazurian troops.
After resolving the conflicts within their own forces, the 12th Battalion fought against and defeated the New Rubinelle Army. Cornering Greyfield, Lin opted to execute him rather than give him a fair trial as revenge for him killing Captain Brenner.
However, Will forfeited his position as leader of the battalion following this when he discovered that Isabella had left to go join IDS and went to go rescue her, leaving Lin as the leader of Brenner's Wolves. Lin's first action as leader was to take some of the 12th Battalion's forces and go on board the Great Owl to assist Will in saving Isabella.
After Isabella rejoined the 12th Battalion along with Penny, Will was convinced to reassume command from Lin and together, Will and Lin led Brenner's Wolves in an attack on IDS's base, The Nest, to obtain the cure for the Creeper Virus which IDS had used to ravage the 12th Battalion's society. Brenner's Wolves proved triumphant and managed to obtain the cure as well as bring down IDS.
Following the defeat of IDS, Lin and Will formed a new society with the civilians rescued by Brenner's Wolves. In the epilogue, Lin is seen checking up Gage's efforts to milk the cows.