Here's an interesting find on the ESRB website. Yu-Gi-Oh! Legacy of the Duelist: Link Evolution is the first game in the franchise to receive a Teen rating from the ESRB. Not even Yu-Gi-Oh! Legacy of the Duelist, the game Link Evolution is based on, received a Teen rating. If you want to know why the game got a bumped-up ESRB rating, you can check out the full details straight from the ESRB listing below.
Content Descriptors: Fantasy Violence, Mild Blood, Partial Nudity
Rating Summary: This is a strategy game in which players engage in turn-based card battles on a grid-like board. Players take turns selecting cards that represent magical creatures with special attacks (e.g., fireballs, energy bursts, lightning strikes). Some cards show characters getting bitten, slashed with blades, or struck by arrows. A handful of cards depict small blood drips or splatters. Some cards contain suggestive material/nudity: a human-like character with her breast exposed (no discernible detail); creatures with exposed buttocks; characters wearing low-cut tops that expose moderate amounts of cleavage.