They're official royal titles that these self-proclaimed aristocrats demand filthy peasants like you address them as.

Identifying oneself as legion gives comfort to other demons.

The royal singular implies a person leads or commands, speaks for, a number of other people.

"We are ready", in example when spoken by the King of England, implies England itself is "ready" for whatever is in the rest of the context of the phrase.

"They" would be the third-person version of this. "They" represents the speaker of the masses, First-Of-Many.

Reusing my comment from a while ago:

A bunch of Transtransformers: https://tfwiki.net/wiki/Category:Transgender_characters

Please note that this is different from "Variable gender characters", where a character's gender differs between iterations/interpretations, rather than actively transitioning in-universe, and can overlap with but is different from "Nonbinary characters" (https://tfwiki.net/wiki/Category:Nonbinary_characters), who trans or no are characters whose gender does not simply fit a binary gender or aren't on a masculine-spectrum/feminine-spectrum gender binary at all. Similarly, this is different from "Genderfluid characters" (https://tfwiki.net/wiki/Category:Genderfluid_characters), where characters show or are stated to have genderfluidity in some way.

41% Over 50% at risk of self-inflicted casualties of the robot wars:

More than 50% of trans and non-binary youth in US considered suicide this year, survey says

The alarmingly high rates of depression, anxiety and suicide attempts are spread across liberal and conservative regions

In California, the most populous state, which recently passed a law to protect trans youth, 44% of LGBTQ+ youth considered suicide and 14% attempted suicide, the survey found; for trans and non-binary respondents, the findings were worse, with 54% considering and 19% attempting suicide. And 70% of LGBTQ+ youth in the state said they had experienced discrimination, with 62% saying they were not able to access mental health care.

The rates of trans and nonbinary youth who seriously considered suicide were similar in the next largest states, at 56% in Texas; 54% in Florida; 50% in New York; 54% in Pennsylvania; 51% in Illinois; 54% in Ohio; 55% in Georgia; 53% in North Carolina; and 52% in Michigan. And 16-20% of trans and non-binary youth reported attempting suicide across these states.

(The Guardian 2022)