The following info comes from a Famitsu interview with Shin Megami Tensei IV director Kazuyuki Yamai.

- Masayuki Doi, known for his work on the Trauma Center games, is the man behind the character design
- Doi was called upon for his talent of being able to design simple characters who also have a strong sense of presence
- along with composer Ryouta Kozuka (Persona 4 and Trauma Team), the two were told to keep a “punk” mindset while doing their work

I told him [Doi] to draw something with a punk mindset. Kozuka, too. I told them, “When players get to see and hear the game, I’d like to have elements that will bring out a feeling of curiosity, rather than relaxation.” For example, the design for the Samurai—we had Doi sketch plenty of drawings while sharing various opinions and trimmed out elements accordingly; which resulted in a simpler finish. Even for the color of their clothing, we looked through several options and settled for blue and white. It’s one of the things that we actually put a lot of thought into.

- development began when Atlus finished Shin Megami Tensei: Strange Journey
- everyone felt it was time for a new numbered entry, especially after fan feedback

“Definitely something simple, yet distinct. I wanted to make something with a ‘punk production’. 20 years ago, fantasy-style RPGs were the standard of the genre. Shin Megami Tensei on the Super Famicom was something like an antithesis when you compared it. That’s what I call ‘punk-minded’. There are many games these days that focus on being enjoyable while relaxing. We’d like to have people enjoy the game and maybe even a shocking feeling towards their views on life and values.”

Link