There is 1 Spirit Mail in the ‘Fields’ area of ‘Kena: Bridge of Spirits’. The spirit mail is in the Forge area and is quite difficult to find. You will have to solve a few puzzles to reach it. This article shows how to solve the puzzles and get the Spirit Mail.
Fields Spirit Mail 1/1
The Spirit Mail is in the underground cavern in the forge area. From the Warp Point, turn around and go down the stairs to reach the underground cavern as shown below.
After reaching the cavern, you will see a tear on a platform in front of you. Shoot the crystal above the tear for water to fall on the tear. This will make the plant grow.
Now throw a bomb at the bombable rock on the right side as shown below. This will make the rock levitate and form a bridge across the two platforms.
Summon forest tear from the plant and guide it through the bridge to the button on the platform on the right side. Use the forest tear to press the button. This will make the water level rise up in the cavern.
When the water level has risen up, swim to the left side. then go through the path shown below to reach the Spirit Mail.
This Spirit Mail unlocks the southernmost house in the village as shown below.