Chapter 20 (Quartet Knights)

Evolution (進化) is the 20th chapter of Tashiro Yumiya's Black Clover Side-Story: Quartet Knights.

Summary
As Luck unleashes his new power, Vetto comments about how Luck has acquired a new spell. Luck thinks about how he has obtained a new power, thanks to visiting the various dungeons and training with Magna. Luck thinks about how he won't let the fight go like Vetto wants, and attacks Vetto.

Elsewhere, Asta and Noelle have been captured by a sand monster. Asta notices that Luck is fight with someone and says that he will come, but Noelle asks how he can go and help with him being in his current situation. Asta says that he will use his crazy muscle power, which Noelle comments about how Asta is an idiot.

Back at the bottom floor, Vetto gets back up and uses his Cheetah Charge spell to charge at Luck. Vetto says that Luck has gotten a bit stronger and to not get carried away, and attacks Luck but Luck dodges. Luck says that he has seen that move before, and attacks Vetto. Luck thinks about how he can't leave a gap between him and his opponent, and that he is not used to this new form. Luck starts to run around and thinks about how he has to settle this before he runs out of mana. As Luck continues his assault on Vetto, Vetto thinks about how Luck is moving around rapidly but he can find Luck's location from his mana. Vetto attacks but Luck appears behind Vetto and says that Vetto has moved. Luck manages to cut off Vetto's arm and thinks about how he has done it. Luck thinks about how he just has to go at it one more time, but suddenly Vetto lands a blow on Luck. Vetto asks if Luck has lost hope now, and comments about how his side can win against the humans.

Luck thinks about how Vetto was able to land a blow even with his arm cut off. Suddenly Vetto manages to reattach his arm, which Luck thinks about how Vetto is using a different kind of magic. Vetto says that he is not going to forgive the humans until they are finished in despair. Vetto charges at Luck, but Asta suddenly appears and blocks Vetto's assault. Asta then lands a blow on Vetto, while Noelle checks to see if Luck is okay. As Vetto recognizes Asta and Noelle, Asta asks what Vetto has done to Luck and that he will be his opponent for now on.