"Prove me wrong." Shikamaru takes Naruto's declaration that he'll be the next Hokage seriously. Sometimes, the simplest validation is enough to change the world.

A new world. This is what Naruto found himself in after he woke up from his near death experience after Kaguya pushed him through her portal with the last of her strength. Thankfully an angel or rather a fallen one happened to be there to give him life once again. Now a reborn as a fallen angel Naruto will face new enemies and challenges like he has never seen before. Naruto/Harem

There were very few things that could rile a 25 year old Naruto Uzumaki up. He was perfectly content to sit in his home, work his normal job, study at a normal school, and in his free time, tinker (read: upgrade in a potentially life endangering manner) with whatever happened to catch his interest. This obviously did not include Devils, or Angels, or Fallen Angels.