Nekoo
Smash Master
Not Only that, it wasn't as if Persona 5 basically revived the JRPG genre to the public and pushed Persona itself making it Mainstream after a long and hard time for the genre, and Sega saying that Persona 5, not persona, but Persona 5 is one of their strongest IP.I'm sorry if this comes off as rude
but to expand your knowledge a bit.
Joker prior to being in Smash has appeared in Persona 5, Persona 5 Dancing and Persona 3 Dancing and Persona Q2 (Japan)
After he got in Smash he appeared in Persona 5 Royal (if you wanna count that), Persona Q2 (Everywhere else) and Persona 5 Strikers.
Also was in a few other crossovers including being a costume in the SMT X FE crossover and Sonic Forces and being in Dragalia Lost and Puzzles and Dragons.
While its not as many games as Rayman or Doomguy he has been in more games than 1, ever.