Tensei Kizoku no Isekai Boukenroku ~Jichou wo Shiranai Kamigami no Shito~

Shiina Kazuya, the protagonist of the story was killed by a stranger in front of a convenience store when he tried to protect two young girls escaping from the stranger who is trying to stab them. The girls fall and are too overcome with fear to get up and continue running away. When Shiina Kazuya awakens he realizes that he was reincarnated as the young noble Cain von Silford, the third son of an aristocrat (Margrave Garm Von Silford) and his second wife (Sarah) in a world filled with sword and sorcery.

Prior to the age of ten Cain grew up in the Gracia Territory surrounded by gods that don't know self-restraint, in the upper echelon of nobility, and a loving family (father Garm Von Silford, mother Sarah, and older sister Raine). At the age of ten Cain is given peerage (Title of Duke, own estate, and an engagement), which leads to him living in Esfort the Royal Capitol.

This is a classic isekai fantasy about an overpowered young man who just wants to be an average adventurer. He has received the maximum level of divine blessings from all seven gods, overcomes any obstacle that comes his way while hiding his unbelievable status and tends to build a harem of highly influential nobles.