In Japanese belief, it is the calm and functional state of a person's soul, or kami, which is considered to be the opposite of Ara Mitama. The Ara Mitama must first be pacified with rites and worship before the Nigi Mitama will appear.
"One of the four aspects of the human soul, as described in Shinto teachings. It is associated with gentleness."
—Shin Megami Tensei III: Nocturne profile
Nigi Mitama can be purchased at Rag's Jewelry once the Demi-fiend has acquired a Jade stone, or it can be fused using to the Erthys and AerosElement demons. Fusing Nigi Mitama with a demon will increase the demon's stats and confer its skills to the demon. However, Nigi Mitama cannot increase a demon's stats past twice its base values and can only transfer skills to a demon with empty skill slots remaining.
Nigi Mitama can only be obtained through fusion or from jewel trade-ins at Rag's Jewelry. By using a Nigi Mitama in the initial mitama fusion, the demon's post-mitama growth focuses on Magic, Intelligence and Luck stats.
Nigi Mitama appears primarily in the DLC Challenge QuestDeath Has Its Applications, and appears as a rare encounter with every Mitama in the DLC quests Experience of the Afterlife and Underworld Money-Maker. They drop 10-Point Card and 20-Point Card, which give Flynn, respectively, 10 and 20 Burroughs App points.
Nigi Mitama appears primarily in the DLC Challenge Quest "A Godslayer Needs Apps," and appear as a rare encounter in the DLC quests "A Godslayer Needs Levels," "A Godslayer Needs Macca" and "A Godslayer Needs Items." They drop and trade 5-Point Cards, 10-Point Cards and 20-Point Cards, and rarely Bead Chains and Amrita Sodas.
Nigi Mitama likes to attempt to negate all incoming damage via its Tetrakarn and Makarakarn skills. Along with Almighty damage virtually being nulled by them, this can potentially leave them unscathed for an entire turn and they may continue this until they flee. Ailments that will keep them from acting can be used to prevent this. Nigi Mitama is vulnerable to Light and Darkness skills.
Fusing any demon with a Nigi Mitama will amplify its Intelligence and Agility stats, increasing its speed and magic resistance. This can be freely done at the Goumaden, or with COMP Fusion provided that the Steiner app is installed.
"One of the four aspects of Shinto thought, it works gently to help maintain a calm mind. It is said to aid in one's relations and sociability, and can lead one in a positive direction."
—Persona 5 background
Nigi Mitama is the fourth Persona of the Temperance Arcana and can only be obtained through fusion in the Velvet Room. It is the first Persona to learn the Divine Grace, Me Patra and Climate Decorum skills.