While not necessarily new, I've been gone for a very, very long time, so might as well be!
As for Shinji, he's a washed-up boxer who left the pro scene several years prior due to the devastating event of losing a child. He's been on a warpath ever since, roaming from city to city to fill the void with whatever he's managed to get his punch-sore hands on, be it liquor, drugs, or sex.
He grew up in the gym — for Shinji to find a new calling in life... they say it's hard to teach an old dog new tricks and for a good reason. Here's to hoping the washed-up boxer can find some peace of mind in Hathian (though, probably not).