Is there a creature who gets it's power and energy from names?

Im starting a campain, and i have figured out what i wanna do with the BBEG, but the problem is, i dont know if there is anything in "the rulebook" that will let me do what i want to achieve.

I need a humanoid creature that can attack through the names of it's enemies, like getting power or something when it says the name of the person it's attacking. I can explain in more detail if needed, but just in case any of my players sees this, i kinda wanna keep it descreet.

Hope there is someone out there who can help