Witcher among Devils (Witcher male reader x DXD)

Witchers.......a race of monster slayers who have helped the humans during the great war and protected them from the angels, devils, demons and fallen angels killing hundreds of them and paying a high price. Losing many of their fellow witchers in the war. After the war only a hundred of them were left roaming on the earth and killing the monsters and stray demons. Among them is a young boy by the name (Y/N) (L/N) who was born from a Witcher father and a sorceress mother giving him a gift for magic and now.....he must walk among Devils for his new contract given to him by the new king of hell, his contract is........killing Riser Phenex.