Fear Names.
Names have power in identity.
Others can use names as weapons.
Names are a hook that can be used to track you...
Remain nameless, and you shall be safe.
~ Planescape: Torment
Multiple D&D subclasses inform the DM about aspects of their world. A cleric's domain informs what deities or forces are present in the world, as does a warlock's patronage. The presence of glamour bards informs one of the many roles of fey in the world, and draconic ancestry sorcerers inform the potential for bloodlines of humanoids and dragons to intertwine.
This list has been further added to with the most recent UA's addition of the School of Onomancy, a wizard subclass that focuses on the role and control of true names. Their flavour text states:
Something that is named stands out in the multiverse, distinct from the tapestry of creation all around it. That distinction creates power that onomancers seek to tap.True names - the concept that knowing an individual's name gives you power over them - are found throughout fiction. From the fairytale of Rumpelstiltskin to the multiple applications of true names in White Wolf's World of Darkness games, to the banishment of DC Comics's Mr Mxyzptlk, the power of names comes in many forms and with many depictions. Dungeons and Dragons has used it multiple times in the past, but this has declined since 3rd edition. In 5th edition published content, the arcane usage of true names is mostly limited to flavour text; the most it can be seen mechanically is with devil summoning:
A mortal who learns a devil's true name can use powerful summoning magic to call the devil from the Nine Hells and bind it into service (MM, pg 67)
On each of your turns, you can try to issue a verbal command to the devil (no action required by you). It obeys the command if the likely outcome is in accordance with its desires, especially if the result would draw you toward evil. Otherwise, you must make a Charisma (Deception, Intimidation, or Persuasion) check contested by its Wisdom (Insight) check. You make the check with advantage if you say the devil’s true name. (Infernal calling spell)Personally, I love the idea of true names. It's an evocative concept that has made its way into multiple forms of fiction, and creates great opportunities for interesting adventures and roleplay. If players want to defeat a powerful enemy, they can go out of their way to seek the villain's true name, learning about their history and the choices they made to get to where they are, then use this knowledge to compel the villain to surrender or change their ways. It also flows in well with the general idea that words and magic are intermingled, as with bards and their songs, paladins and the oaths they swear, and the words of power within the D&D spell list.
I fully support the presence of true names in D&D, and that's why I cannot say I'm the biggest fan of the onomancy wizard.
