Soul (in addition to being one of Krillix's domains) is a currency in the PentPlane.
Souls are used to activate Constructs (1 Soul) and are accepted by Gachapons (3 Souls).
Souls can be obtained by:
- winning random combats in the PentPlane (1 Soul)
- defeating a Construct (3 Souls, for a net gain of 2)
- purchasing a reward from a Gachapon (3-7 Souls)