Koneko toujou

YN gremory had a good life with his family until one day when he was playing with his sister Rias gremory a group of fallen angel attacked them YN sacrificed himself for Rias to escape after being captured a man with some strange armor named Laurence Barnes mostly known as prophet rescue him he take him in years of military training Laurence Barnes died of old age he gave YN his nanosuit and the name prophet and his predator bow now he is on the search of his family