The Seven Deadly Sins are mini-bosses that can be encountered on any floor in their respective Mini-Boss rooms outside of The Chest and Dark Room. Unlike with regular bosses, there is no special door leading to a mini-boss room, meaning that there is no way to tell whether a room is inhabited by a mini-boss unless the player has an item that reveals map icons such as Compass or a Map item. Once in a mini-boss room, the player cannot escape through means of bombing the door, as it will be boarded off.
Each of the Sins has specific drops, that are consumables or a pedestal item (less frequently).
In a room containing multiple Sins, only the last one will drop something, allowing you to choose what drop you want by killing a certain mini-boss last.
All of them are based on the Seven Deadly Sins.
These are much stronger alternatives to the original sins, known as the Seven Super Deadly Sins.
There is an Ultra variant of both Pride and Greed. Ultra Pride resembles Edmund and Florian, while Ultra Greed serves as the final boss for Greed Mode.