Otak Shrine is in the northwestern part of the Hebra Mountains, inside of Icefall Foothills Cave.
Shrine Location
Otak Shrine is at -4392, 3714, 0212. It can be found in Icefall Foothills Cave, in the northwestern part of the Hebra Mountains.
Proving Grounds: Traps
Take the weapons near the stairs. There are various traps in this area that you can use to your advantage, such as flames on ropes above dry leaves, boulders held up by a wooden plank, and so on.
After you defeat all the Constructs, the gate opens. Go through and open the chest to get a Construct Bow. Then check on the dragon ring to get a Light of Blessing and complete the shrine.