These small tokens contain their respective kami. Activating these single-use fetishes releases a ten foot diameter sphere of the contained element. The element can be directed to appear up to 20-30 feet away from the nemuranai (helpful when releasing a huge fireball) and can be altered from a perfect sphere into another shape of similar dimensions (but not intricately; the purpose of the nemuranai, and the will and ability of the kami, is to produce a mass of elemental material).
Fire, water, and air can be directed forth like a flamethrower, firehose, or airhose as appropriate. Earth can be summoned as several boulders and rocks instead of one large chunk.
In order to form one of these nemuranai, a sufficient volume of appropriate material must be stored within. This means a water fetish drains a pond, an earth fetish can leave a crater in the ground, and a fire fetish requires a bonfire or other large source of flame to extinguish. The fetishes do not create their element; they store it.