A lake named after the fallen Zoran Hero from Majora's Mask makes its dayview in The Legend of Zelda: Breath of the Wild. Mikau is my favorite character, so I spend my time hanging out by this particular lake. An idea struck me then.
When the Winter Solstice occur, a vortex whirls to life, and Mikau's spirit would manifest from the lake. From there he will open the dimensinal portal to lead the one before him to his home realm of Termina. Only those with a rightous heart can see his spirit.