At the beginning of Hyrule Warriors, Link is a young untested Hyrulean Forces recruit and like the other trainees wears a Trainee Tunic as his standard uniform. It features a surcoat and chain mail armor, however unlike his fellow trainees Link does not where the uniform's helmet. During the Armies of Ruin scenario, Link first appears wearing his Trainee Tunic while sparring with one of his fellow cadets (who is wearing Trainee Tunic and Helmet). Link's sparring partner tries to take advantage of Link's lack of a helmet, but Link well aware that his helmetless head is a prime target uses his Wooden Shield to block his sparring partner's Wooden Spear and skillfully retaliates with a Jump Attack, catching Zelda's attention briefly before she is interrupted by a Hyrulean Forces' messenger.
While Zelda, Impa, and the more experienced soldiers and captains fight the Dark Forces lead by Volga and Wizzro, Link and the other trainees are forced to stay behind at the Castle walls. However, Link refuses to stand by as the Princess and Hyrulean Forces fight valiantly to defend Hyrule. While still wearing his Trainee Tunic, Link grabs a Knight's Sword and Shield, Link heads on to the battlefield to aid Princess Zelda, Impa, and the Hyrulean Forces. During the battle, Link comes across a Fairy named Proxi who decides to join Link as his Fairy Companion in exchange for protecting her from the Dark Forces. Link manages hold his own against the Dragon Knight Volga, but is momentarily overpowered. Fortunately he is saved by the intervention of General Impa. Volga tries to kill them with his fire breath, however Link's Triforce of Courage shields Link and Impa from the flames and Volga retreats. Link continues to assist the Hyrulean Forces against the Dark Forces and aids Impa in reaching Princess Zelda and her troops fighting in the central part of Hyrule Field. Recognizing Link from the Castle Training Yard, Zelda is informed by Impa of Link's heroics. Link then aids Princess Zelda in her plan to summon the Great Fairy in order to take out a large portion of the Dark Forces troops and win the battle. Zelda's plan succeeds, however Wizzro summons King Dodongo. Link eventually manages to defeat King Dodongo, however while he and the Hyrulean Forces were distracted, Wizzro infiltrated Hyrule Castle. Link rushes back only to find a group of monsters waiting for him, which are dispatched by Impa. Impa informs Link that Princess Zelda has gone missing and that she will need his aid to find her. Recognizing Link as the reborn Spirit of the Hero, Impa gives Link the Hero's Clothes to replace his Trainee Tunic. Link then switches to wearing the Hero's Clothes for the rest of the game.
The Trainee Tunic is the default Tunic Link starts out with, though following the Armies of Ruin it is replaced by the his tradition Green Hero's Clothes. However Link can switch back to it anytime when selecting a Warrior and opening the Costume Selection Menu (which gives Link access to any outfit he has already obtained). Like other costumes in Hyrule Warriors the Trainee Tunic has no effect on Link when worn and is simply an alternate outfit.