Magic of a Name

True Names   

A true name is the name by which a self-aware creature identifies itself. This name might be the name a person was given at birth, or one a person chose or earned later in life. Whatever a name’s origin, the simplest way for you to know your true name is to think truthfully about yourself and then think, “My name is...” Your true name is how you finish that sentence. You can try to hide your true name by using a pseudonym, but you must be wary not to inhabit that false name too deeply. If a false name comes to be the best expression of who you are, it becomes your true name. Changing one’s true name is never a quick choice; it’s something that happens over time as a name becomes the creature’s truth. As a quick guide, a creature has a true name if it understands at least one language or it has an alignment.  

The Magic of a True Name   

The Sidhe are the masters Onomancy, although any can learn such magics, the Sidhe have an innate connection with it. At its simplest, knowing a creature's true name allows you to Scry on them without the need for a saving throw.  

A Blessing and a Curse   

You can bend magic to assist or hinder creatures through the power of their true names. You can cast the Bane or Bless spells, only affecting creatures within range that you speak the true name of, without expending a spell slot if you speak the true name of the target of the spell as part of casting it. If you are a caster, these spells count as class spells, and are always prepared, but don’t count against the number of spells you can have prepared, or the number of spells you can know. You can cast the spells in this way a number of times equal to your Charisma modifier (a minimum of once), and you regain all expended uses when you finish a long rest.  

Additionally, as a bonus action you can speak a creatures true name, causing them to be either Charmed or Frightened of you until the end of their next turn. 

Such a Pretty Name   

Through the use of a creature’s true name, you can gain better control over them. If you speak the true name of the target while casting a charm spell, the creature has disadvantage on saving throws against being charmed by you, and when they cease to be charmed by you, instead of knowing they were charmed, they believe the thoughts and actions done while charmed were their own choice. Additionally, if the charm affect would end by the creature being attack or having a spell cast upon them by you or an ally, they inside must make a new saving throw, if they fail they are still under the charm affect.