Prince forms are the forms that the Sins go into if their sin is either not committed or committed too much.
Demons with a prince form are called "prince demons", there are more than just the sins who are prince demons and basically all of them are born in royalty.
Their prince forms act as their "true forms", the forms that they would constantly be in if it wasn't for them being taught to stay calm and have morals from their mothers, the Virtues. Despite this tho, all of Dwurm's prince demons have a calm side, tho, those who are born in evil, rarely go calm.
If the sins were born from anyone but the Virtues, they would be consumed by evil and sin, and not be as friendly or calm as they are in their typical "relaxed" state.
The Prince Forms typically have their own set of mind and memories, they almost act as a second person, typically, the Prince forms remember things that the relaxed state has done or gone thru lately, but the relaxed state doesn't remember that they ever turned into their Prince form. However, sometimes the prince form forgets major things, such as who their friends are or what their relationships with a person is.
However, a prince demon with two sides are able to "tame" themselves, which makes it so that no matter what form they're in, they remember from each other and work "together".
The Sins are the strongest Prince Demons, Lucifer being the strongest of them all at the current moment. While there are also black boned Prince Demons, they don't exceed the strength that Lucifer can get to, his purple nose is misleading (partially).
Also, the females still go by Prince, just like how male ladybugs are still called ladybugs.