Isekai wa Smartphone to Tomo ni.

A 15-year-old boy, Mochizuki Touya, dies in an accident involving lightning and is confronted by God, who admits to making a mistake. Despite this, God offers to reincarnate Touya into a fantasy world, allowing him to retain his smartphone. Touya begins his journey in a pseudo-medieval setting filled with swords and sorcery. His adventure includes various experiences and encounters, as he moves from place to place, pursuing whatever interests him. The story features elements of wonder and unexpected solutions to challenges.