Summoning

Summoning is the process by which you can obtain new criminal girls by expending crystals. Summoning a girl also costs 1 Curse.

Crystals
There are 7 types of crystals: Greed, Gluttony, Anger, Lust, Envy, Sloth, and Pride. These crystals can be found in Labyrinths from Sparkles.

Resources
To summon a girl, you must select 4 types of Sin Crystals. You must have at least 50 of each crystal to attempt a summon. Also, you will consume 1 Curse each attempt, which are obtained by doing quests.

Rarity
The rarity system is based on the background of the girl.
 * Common: Yellow
 * Uncommon: Red
 * Rare : Blue
 * High Rare : Shining Yellow
 * Super Rare - Gold

Recipes
The kinds of resources used do not seem to determine what sin you get, or at least have only a little impact.