Normally when I play a game with a nameless male protagonist I name the guy "Jay", the closest male variant of my name, and also a nickname my sisters call me. With Megaten however I put a little more thought in it.
I used the name "Shin Hajime" for the Demi-Fiend in SMT3, as in "shin" for new/true and "hajime" for beginning. Is it possible for this to be a proper Japanese name? I have absolutely no clue. "Luc" was my demon name as Lucifer was already taken. My bro called him "Akira Fudou" from Devilman in his second playthrough.
For DSRK I named him "Raidou Kuzunoha" which kinda ruined the impact of the ending when Kaya calls you by your real name. ^^;; Going through a (Tezuka Osamu's) Black Jack obsession I named him "Kuroo Hazama" in the second playthrough.
Moving onto a Devilman phase, I named Persona 3's protagonist "Ryo Asuka", just 'cause it has a nice ring to it. He's called
Kitaro in one of those silly nico nico videos.
In Persona 4, I used "Yukimura Sanada" and it just so happens that his English voice actor, Johnny Yong Bosch, voiced Yukimura Sanada in Warriors Orochi! Freaky coincidence?! He's referred to as
Bancho, a leader of a group of juvenile delinquents in that same nico nico video. Izanagi sure looks like he could be one.