Asta and Yuno were abandoned together at the same church and have been inseparable since. As children, they promised that they would compete against each other to see who would become the next Emperor Magus. However, as they grew up, some differences between them became plain. Yuno was a genius with magic, with amazing power and control, while Asta could not use magic at all, and tried to make up for his lack by training physically. When they received their Grimoires at age 15, Yuno got a spectacular book with a four-leaf clover (most people receive a three-leaf-clover), while Asta received nothing at all. However, when Yuno was threatened, the truth about Asta's power was revealed, he received a five-leaf clover Grimoire, a "black clover"! Now the two friends are heading out in the world, both seeking the same goal!
Personally its the best new series in Weekly Shonen Jump since the conclusion of Naruto's epic story (not to say Boruto isnt just as awesome).
BLack Clover has very high friendship values, epic battles, deep character interactions, stunning landscapes and magic, and awesome dungeons and explorations that cant be found in any other manga currently. The anime adapts this wonderful and carries the same level of feeling that the manga gives me week after week, please check it out.