Mob kara Hajimaru Tansaku Eiyuutan

Kaito Takagi is a high school student who spends a lot of time killing slimes and finding Dragons in japan. He hunted a lot of slimes and got extra money for it and this search brought him so far. He found a rare skin slime and then killed it after that he got a special grade card. This card helps them summon Mythical begins. He can start his new fantasy life with that card. He has a beautiful childhood friend in his school.