Koby made his debut in the Romance Dawn arc. From a very young age, Koby wanted to become a Marine, but his dreams were put on hold after he accidentally boarded Alvida's ship. Alvida did not kill Koby, instead, she kept him on the ship and made him a cabin boy. Koby had to quietly suffer until he met Luffy, who taught him the importance of fighting for his dreams.
With Luffy's help, Koby was finally able to join the Marines, and pursue his dream. Koby has been involved in some of the biggest incidents in the series, but none of them have had as big of an impact on his life as the time he went to Amazon Lily. Koby was tasked by the higher-ups to go to Amazon Lily to capture Boa Hancock, which was not an easy job at all considering that she is among the strongest characters in One Piece.
Protecting Everyone
When Koby arrived at Amazon Lily, he had no idea that the Marines would have to face the Kuja as well as the Blackbeard Pirates. The fight between the three groups was chaotic, and it allowed Boa Hancock to turn the Marines and Blackbeard's underlings to stone. The Marines were heavily outnumbered, but after unleashing the Seraphim, the tide began to turn. As many of the Marines were under the effect of Boa's devil fruit, they were susceptible to being destroyed by the Seraphim's attacks. So, Koby had no choice but to order them to stop.
This created an opening, and it allowed Blackbeard to capture Boa, after which, he threatened to kill her. Luckily for Boa, Koby managed to stall the Emperor until Rayleigh's arrival. The right-hand man of the Pirate King had garnered a notorious reputation, and he managed to de-escalate the situation. The time that Koby bought was precious and there is no telling what Blackbeard would have done. So, it is fair to say that all the parties were indebted to Koby. Unfortunately, Koby wasn't so lucky as he was surprisingly kidnapped by Blackbeard.
Serving As A Pawn
On the first impression, it seems that Koby is in a heap of trouble as the Blackbeard Pirates are infamous for killing some of the most well-known characters in the series. So far, the crew has been responsible for the deaths of Whitebeard, Ace, and Absalom, which shows that they wouldn't hesitate to kill Koby for their needs. However, one thing to keep in mind is that the crew only hunts devil fruit users, and Koby does not possess one. So, why did Blackbeard kidnap him?
While Koby does not have any ridiculous devil fruit power, he is a member of SWORD, a top-secret organization. SWORD was created for unknown reasons, and one of its duties is to monitor the activities of the Four Emperors. It seems suspicious that a secretive group would be created just to observe the Four Emperors, so, it is safe to assume that SWORD has bigger motives. Up till now, a total of five members have been revealed, which include- Koby, X-Drake, Hibari, Prince Grus, and Helmeppo. Koby could provide Blackbeard with crucial information that could help the latter in his goals. Also, Blackbeard can use Koby to disarm the Seraphim, as they seem to follow his orders. This could come in handy during Blackbeard's future sieges.
Meeting A Former Ally
Despite being a captive of the Blackbeard Pirates, all is not lost for Koby. While traveling with the Blackbeard Pirates, Koby can actually meet former Marine Admiral, Kuzan. During the Punk Hazard arc, it was revealed that Kuzan had quit the Marines after losing the fight against Sakazuki. At that time, Kuzan never explicitly stated that he joined the Blackbeard Pirates. It remained hidden until the Dressrosa arc, and even then Oda gave no explanation as to why Kuzan joined the crew of an Emperor of the Sea. It doesn't make sense for undoubtedly the most sensible Admiral to join the most notorious pirate crew in the world. Clearly, Kuzan has ulterior motives, which remain a mystery, but that will change in the future.
A prevalent idea surrounding Kuzan is that he might be the head of SWORD, and joining the Blackbeard Pirates was just a way to maintain his cover. Kuzan's move to Blackbeard Pirates is definitely suspicious and even some of the Emperor's crew members are wary of him. Back in the Dressrosa arc, Burgess told his captain that he did not trust Kuzan, but Blackbeard played it down. When Doflamingo encountered Kuzan at Punk Hazard, the former immediately understood that the former Admiral had a motive. Kuzan has also been known to have connections to the Underworld, which is unusual for a person like him. Koby's possible meeting with Kuzan could change a lot of things.
Will Koby Make It Out Alive?
Koby's future is up in the air, and his chances of escaping Hachisnosu are slim. It is impossible for him to escape on his own, and the Marines don't seem to have any plans to rescue Koby. Either Koby has to miraculously pull off an escape on his own or Kuzan will aid him. The longer Koby stays with the Blackbeard Pirates, the lower his chances of survival.