In The First Volume,The Protagonist (Jacob) Gets Hit By A Car And Reincarnates Into Another World.In His Previous Life,Jacob Was Mentally Disabled And Spent His Time Alone At Home.In His New Life,He Reincarnates As A Young Child In A Family Of Peasants.He Discovers He Can Use A Rare Type Of Magic Only Used By A Legenday Hero Over 900 Years Ago During The Raneth Invasion,A Species Of Insectile Monsters With Human-Like Intelligence That Have Carapaces Stronger Then Tungsten,Capable Of Using Both Magic And Weapons As Well As Dragon Mounts.