The official Japanese site for Hyrule Warriors Legends has been updated, and as expected it features playable character Skull Kid, a bit more of the Wind Waker stage and a new enemy in the form of Phantom Ganon. All of these elements were confirmed by a recent Famitsu feature.
Skull Kid is one of the most iconic characters in the entire Zelda franchise, having made his debut in Ocarina of Time before taking on a larger role in its direct sequel, Majora's Mask. This version of Skull Kid is based on his Majora's Mask incarnation.
Phantom Ganon is another recurring character from the Zelda series, and in this particular case is based on the enemy seen in Wind Waker and Four Swords Adventures.
Finally, a little more of the new Wind Waker-inspired level is shown. We've already seen something of this stage previously, but what we believe are three new screens - the bottom row of the composite image above - have been released. It pulls together elements of the GameCube (and later Wii U) classic to create an entirely new world to explore and do battle in.