The two main characters in Black Clover are Asta and Yuno. Asta possesses the rare five-leaf clover grimoire, whereas Yuno is the rightful heir to the Spade kingdom's throne. Throughout the series, they both demonstrate their abilities against a variety of formidable foes. Fans are well aware of Asta and Yuno's friendly rivalry. Despite being diametrically opposed, the two are close friends. They both grew up in the same orphanage and regard each other as rivals. Asta had always wished for magical power, but he never received it. His life, however, began to change when he received his grimoire.
A rare grimoire with four leaves, thought to bring luck, was also given to Yuno. The best Magic Knight Squad in the kingdom hired Yuno, while the worst squad chose Asta. He continued to strive to become the Wizard King despite this. Asta and Yuno encountered a number of foes along the way who grew more powerful every day as they worked toward achieving their objective. It is obvious how much they have grown from the time when they were just beginning their journey from the Forsaken Realm to the Royal Capital. They were always equal to one another, as it turned out. Who would prevail if they engaged in a direct fight, though?
Physical Prowess Between Asta and Yuno
Asta would definitely have the upper hand against Yuno in terms of physical strength. Since Asta didn't have any magic, he did whatever he could to become stronger, training relentlessly to build up his physical strength. In the end, his efforts were not in vain, as he is able to do over a thousand push-ups without a break. The swords he received in his grimoire are extremely heavy and yet he can wield them without any problem.
Moreover, the Queen of the Witches enhanced Asta's arm strength using Blood Magic when he was hexed by Vetto. On the other hand, Yuno was blessed with extremely powerful wind magic. Ever since he was a child, he relied on his magic rather than brute strength for every little thing. Even when he became a Magic Knight, he never had to use physical attacks because of his overwhelming magic.
Magic and Skills Between Asta and Yuno
Asta doesn't possess any mana, but his grimoire allows him to nullify all kinds of magic regardless of how strong it is. Moreover, unlike those with magic who drain their mana during battle, Asta doesn't have that weakness. He can go on fighting as long as it doesn't drain him physically. In addition, although he cannot sense mana, he can sense ki. In that sense, he has the upper hand against his enemies because although they won't be able to sense Asta because of his lack of magic, Asta can sense them from a distance. This makes it easy for him to form sneak attacks against extremely powerful enemies.
On the other hand, Yuno has a massive reserve of mana as a member of the royal family. He has a wind attribute, meaning his attacks are very flexible and versatile. Wind mages are known for their keen senses, including hearing, eyesight, and mana detection. Unlike Asta, who is a close-range fighter, Yuno can fight the enemy head-on as well as from a distance. He can cast two powerful spells at the same time -- something even strong mages have difficulty with. Moreover, he has the wind spirit by his side to help him out in battle. Yuno is especially skilled in Mana Zone and wielding spirit magic.
Spirit or Host Between Asta and Yuno
Asta is the host of a low-ranking devil named Liebe, who possesses Anti-Magic. Liebe was a devil from the first level of the underworld who resides in Licht's grimoire and chose Asta as his next wielder. Just like Asta, Liebe possesses no mana and is unable to use magic. Therefore, he can use Anti-Magic without suffering the weakening effects since he has no mana to drain. The fact that Asta is able to use Anti-Magic is only because Liebe chose him. Asta's Devil Union allows him to further enhance his anti-magic abilities. The power is so great that he can nullify a Gravity Singularity and coat weapons with Anti-Magic.
Conversely, Yuno was chosen by the wind spirit Sylph. The fact that a spirit chose him has something to do with both strength and luck. Sylph once mentioned that he was chosen only because of his unparalleled magic and talent. Sylph always stays by Yuno's side, and the latter can ask her to assist him in battle anytime. Just like Asta and Liebe who use the same element, Yuno and Sylph also share the same attribute. Therefore, once Yuno gains Slyph's powers for his own, he can dominate his enemies with ease.
Who Would Win in a Fight Between Asta and Yuno?
Both Asta and Yuno would suffer significant losses in a serious one-on-one conflict because they are both powerful individuals in their own right. They have fought many challenging battles and displayed significant improvement since joining the Magic Knights Squad. They have faced enemies, particularly in the Spade Kingdom, that even the Squad Captains find challenging. Due to Yuno's superior speed, Asta can only partially counteract Yuno's wind magic in a fight. However, he is unable to dodge all of Yuno's attacks. Asta's extraordinary physical strength would also present a challenge to Yuno.
Even if Yuno used powerful techniques such as Mana Zone and Spirit of Boreass, Asta could render these useless by uniting with Liebe, who is far more substantial than Sylph. In terms of stages, Yuno is a Stage 0 mage -- the highest rank any mage can get. However, normal magic doesn't do well against devils. On the other hand, Asta is an Arcane mage, who is the host of a devil. Therefore, despite being one of the strongest mages in the series, Yuno will most likely lose against Asta. Regardless, even if Asta were to win, it wouldn't be without consequences, as Asta would have a difficult time defeating Yuno.