Things You'll Need
Instructions
Go to Ikana Valley on the third day and stand in front of the entrance to Sakon's Hideout. A wooden sign marks this entrance.
Equip the Bunny Hood, if desired. Position Link in front of the crack in the mountain on the right side of the entrance.
Roll into the crack at an angle until Link pops through the crack and lands in Sakon's Hideout. Link may fall in the water next to the hideout if you do not position him correctly. If this happens, you go back to the Ikana Valley entrance.
Equip any type of mask, excluding the Keaton mask. Wait for a small boy, Kafei, to enter the room. After Kafei talks to Link, you take control of Kafei.
Press "Start" to pause. Scroll to the "Masks" page. Equip the Fierce Deity mask. Press "Start" to return to the game.
Complete the puzzle in the room as Kafei. When you do, you regain control of Link. Link transforms into the Fierce Deity. Help Kafei get the Sun Mask in Sakon's Hideout. When he gets the Sun Mask, you go back outside.
Get in the river and let the current carry you to the swamp. Once in the swamp, you are free to wear the Fierce Deity mask anywhere.