Sinful Indulgence Sources

Sinful Indulgence (often referred to as a sin) is the rare material used for enlightening units for the last step in each gate. This material is in limited supply to free players but is sometimes available from enlightenment summons as step rewards or for gems or from bundles. Note that there are also Otherworldly Indulgence which are used to enlighten collaboration units from other worlds (i.e. not the ones that are alternate versions of our normal units), but they are more plentiful and are usually obtained from collaboration events.

Regular Supply

 * Friendship Coin Exchange - 1 available for 2000 friend coins monthly
 * Summon Coin Exchange Shop - 1 available for 500 summon coins weekly
 * EX Coin Exchange - 1 available for 500 EX coins and 1 available for 2000 EX coins (2 week refresh)
 * TAC Coin Exchange - 1 available per week for 5 TAC coins
 * Consecrated Elements - usually runs for 2 weeks every month. Doing the daily for a week gives you access to the bonus quest which gives 2 sins (so you can get 4 a month)
 * PvP Coin Exchange - when the event runs there are usually a few available for coins
 * Battle Coin Exchange Shop - when the event runs there is usually one available for coins

Event Acquired
Most free sinful indulgence are obtained through events, some of which will run periodically or are permanent, and some of which are only expected to run once. We aren't generally informed which events will rerun again later.

New events are no longer being added to this list as there are quite a lot of sources of sinful indulgence now. For a list of quests which provide sinful indulgence from milestones or quest missions, see Sinful Indulgence.