Roronoa Zoro was the first person in One Piece to join Luffy on his journey to become the Pirate King. Luffy saved Zoro from being killed in Shells Town. It took Luffy some time to convince Zoro into becoming a pirate as the latter was a bounty hunter, who became famous for catching pirates. Ever since leaving Shells Town, Zoro has been a valuable asset for the entire crew.
He is an outstanding swordsman, who dreams of becoming the Strongest Swordsman in the World. It is a big dream, but Zoro won't let anything stop him. It is clear that Zoro has his eyes set on Dracule Mihawk, who currently holds the title. So, will Zoro be the person to take down Mihawk, or will he have a different final opponent by the time One Piece is over?
Zoro's Power So Far
Many fans deemed the Wano Country arc to be Zoro's arc, where he would uncover the secrets about his past and gain new powers, and it is fair to say that Oda did not let fans down. Zoro had to give up Shusui as it belonged to the legendary samurai, Shimotsuki Ryuuma, however, Zoro received a much better sword in exchange. Kozuki Hiyori offered Zoro Enma, which used to be Oden's sword. Enma is one of the 21 O-Wazamono grade sword, and it is a part of a prestigious list of weapons that have managed to scar Kaido.
The blade was crafted by the legendary swordsmith, Shimotsuki Kozaburo. The sword has the unique ability of drawing out Armament Haki from its user, which makes it an incredibly dangerous blade as it could result in the death of an individual. Furthermore, Enma has the potential to improve further. According to Tenguyama Hitetsu, if Zoro can turn Enma into a black blade permanently, then it could lead to an increase in the sword's grade. So, Enma could become a Saijo O-Wazamono grade sword. With the help of Enma, Zoro managed to defeat King, who is Kaido's strongest underling.
Duel With Mihawk
After being humbled by Mihawk during the Baratie arc, Zoro grew even more determined to take his throne. Since the Shichibukai was dissolved, Mihawk is going to be hunted down by the Marines, so it would be a foolish decision for him to stay in one position. Mihawk will very likely travel to the New World, where it is very likely for him to cross paths with Zoro.
The buildup to Mihawk and Zoro's fight has been developing for a very long time, in fact, Mihawk is extremely keen to see Zoro surpassing him and claiming the title of the Strongest Swordsman in the World. Before Zoro does fight Mihawk again, the former needs to improve his swordsmanship skills even further. It took Zoro a lot of effort to defeat King, and Mihawk is very likely stronger than King, so Zoro needs to become even better if he wants to take down Mihawk.
Future Abilities
In the Wano Country arc, it was revealed that Zoro possesses Conqueror's Haki. After Kaido and Luffy displayed that Conqueror's Haki can be combined with attacks, Zoro needs to improve his control over it. Zoro's Conqueror's Haki is still raw and with a blade such an Enma, which draws out the user's Haki, it can help Zoro massively in future battles. However, Zoro cannot rely on Enma's ability all the time, thus, he needs to train even more to get a better control over his Conqueror's Haki.
Unlike Mihawk, Zoro does not have a Saijo O-Wazamono grade sword. It is quite apparent that the higher the grade of the sword higher will be its destructive power. Before he faces Mihawk, Zoro needs to get his hands on a Saijo O-Wazamono grade weapon, or he could also try to turn Enma into one. Either way it is important that Zoro manages to get a Saijo O-Wazamono grade weapon. The combination of better Conqueror's Haki control and superior swords would allow Zoro to take down Mihawk.
His Final Opponent
Zoro will very likely fight against Mihawk, but there is a chance that the legendary swordsman might not be his final opponent. There is a chance that Mihawk could be captured by the Navy, or he could even be killed by some other pirate. According to multiple theories, the Straw Hats' final opponents could be the Blackbeard Pirates. So, it would mean that Zoro would have to fight more opponents after Mihawk.
If the Blackbeard Pirates are the final opponents of the Straw Hats then Zoro would have to fight against Jesus Burgess, who is the captain of the first ship of the Blackbeard Pirates. While Burgess does not possess any kind of blade, he is the right-hand man of Blackbeard and so far Zoro has usually fought against the second-strongest member of the enemy crew. Zoro's fight against Burgess would definitely be an exciting one, and it would be interesting to see how Zoro fights a person, who utilizes no swords at all.