The Egghead arc is the first one in the final saga of One Piece. It is primarily focused on Egghead Island, which is the home of Dr. Vegapunk. It has been called "Future Island" because of the incredible technology present on it. The Egghead arc includes many major revelations that have completely changed the fans' opinion of certain characters.
Along with disclosing major secrets, the arc has also featured some epic battles involving some of the biggest names in One Piece. The fights between the characters have been enthralling, but some of them have been more captivating than others.
6 Kid Vs. Shanks
After Eustass Kid left Wano, his destination remained unknown for a long time. It was confirmed in the Egghead arc that he was on his way to Elbaf. Once he was near the island, Kid found out that the Red-Hair Pirates were docked at the same place. So, Kid decided to attack the island, as he considered it an opportunity to seek revenge against Shanks for cutting off his arm.
As the Kid Pirates drew near to the shore, Shanks used his Kenbunshoku Haki to see the future. In his vision, Shanks saw Kid causing massive damage to his fleet, so the Yonko decided to rush toward the Supernova. Before Kid could even prepare himself, Shanks used Divine Departure to knock him out. This fight demonstrated how powerful Shanks really is and solidified him as a serious contender to claim the One Piece.
5 Kaku Vs. Zoro
Kaku and Zoro fought each other at Enies Lobby, where the Straw Hat had to unlock the Ashura to defeat his opponent. Kaku was kicked out of CP9 and then promoted to CP0 alongside Lucci. Both Kaku and Zoro have improved a lot strength-wise since their last meeting.
Kaku has mastered his Devil Fruit ability, and he can also tap into its Awakening. The duel between Zoro and Kaku was intense, and it was difficult to predict who would come out on top. Unfortunately, before the fight could reach its conclusion, Kaku was knocked out by Stussy.
4 Luffy Vs. Lucci
Luffy and Lucci have a lot of history. The two go all the way back to Water 7, where they fought each other for the first time. Lucci emerged as the winner in their first confrontation, but Luffy won the subsequent battle at Enies Lobby. After being defeated by Luffy, Lucci was kicked out of CP9, but he was promoted to CP0. Since then, Lucci and Luffy never faced each other until the Egghead arc.
Once again, they were on opposite sides: Lucci had to kill Vegapunk, while Luffy had to protect him. Lucci was confident that he would defeat Luffy with the help of his Devil Fruit Awakening. However, he was proven wrong when Luffy obliterated him using his Gear Fifth. It was an easy victory for Luffy, who was in complete control of the fight from the very first minute.
3 Blackbeard Vs. Law
Blackbeard's involvement in the Wano Country arc was kept to a minimum by Oda, which was a smart decision considering there were already two Yonko involved in the arc. Blackbeard has been in the spotlight in the Egghead arc. In the early parts of the arc, Blackbeard ambushed Trafalgar Law near Winner Island.
The two members of the Worst Generation then proceeded to clash with each other on the island. Fans were expecting Blackbeard to dominate the fight, but Law managed to surprise everyone with his combative abilities. Before going all out, the two made a bet that whoever came out on top would take the other's Road Poneglyphs. The result of this fight is still unknown.
2 The Straw Hats & CP0 Vs. The Seraphim
After Stussy betrayed and incapacitated both Lucci and Kaku, they were locked up to stop them from causing any more problems. The Straw Hats were under the impression that they could finally rest easy as their enemies were in chains, but they couldn't have been more wrong. As a result of York's defection, the Seraphim were programmed to attack every person on Egghead Island.
Due to their incredible durability, even Luffy and Zoro failed to damage them. As the Seraphim were also attacking CP0, the assassins proposed an alliance that would see them help each other out. With no other option, Luffy and Zoro accepted and freed them. The four began fighting against S-Bear and S-Hawk. The fight between the two groups is still ongoing, and it doesn't seem to be any closer to reaching its conclusion.
1 Marines Vs. Blackbeard Pirates
The Blackbeard Pirates are agents of chaos; they stir things up whenever they are involved in the story. The crew traveled to Amazon Lily to steal Boa Hancock's Devil Fruit, but Rayleigh's intervention prevented them from causing her any serious harm. However, the Blackbeard Pirates refused to go back empty-handed, so they decided to kidnap Koby.
Blackbeard's reason for kidnapping Koby remained unknown until Chapter 1080, when the Yonko finally gave away the information. Blackbeard wanted to use Koby as a bargaining chip to strike a deal with the World Government. The Yonko had no idea that Koby's mentor, Monkey D. Garp, would turn up at Hachinosu along with other Marines. The fight is still ongoing, and at the moment, it is difficult to predict a winner. But one thing is for sure: This is undoubtedly the best fight in the Egghead arc so far.