What is Ren Amamiya?

The protagonist of Persona 5/Persona 5 Royal, not much to say, he is a silent protagonist.

Also called
Joker - Codename
Akira Kurusu - The part of the fanbase that clings to hope that this is still canon.
Attic Trash - by Goro Akechi
Leader - By the Phantom Thieves of Hearts
This Guy - By voice acting
Ren-Ren - By Ryuji Sakamoto