Years ago, when Alucard and Golden Lion Shiki launched their two-pronged attack on the World Government and Marineford, Alucard infiltrated the government and posed as a Celestial Dragon for six months, which is when he met Hancock and her two sisters.
Shiki, on the other hand, was defeated and imprisoned in Impel Down again. Kong was so furious he wanted to kill Shiki on the spot, but Alucard, along with another Celestial Dragon, petitioned the Gorosei to spare Shiki's life, allowing him to survive.
However, the final stages of the battle were chaotic. While Shiki's great fleet suffered heavy losses, some members, including Matthew and Stragus, managed to escape.
As Golden Lion's second-in-command, Dr. Indigo had not directly participated in the fighting. He had been stationed at the rear, in full control of the beasts infected by Alucard's Blacklight Virus, and overseeing the live broadcast of the war from the Sabaody Archipelago.
When the war was nearing its end, Dr. Indigo could already see that Shiki was going to lose; he knew his captain too well.
Dr. Indigo was loyal to Golden Lion, but not enough to die with him. What's more, Shiki had gone into the battle with the idea of "I'm here to stay."
After the war, Dr. Indigo and a few of Shiki's loyalists, including Stragus, formed a pirate alliance. They made several unsuccessful attempts to rescue Golden Lion, then sailed around the Grand Line.
Although Dr. Indigo was not a combatant, and his strength was only slightly above average, his position as Shiki's former second-in-command gave him a high standing within the alliance.
When they tried to re-enter the New World, the era of the Three Monsters and Whitebeard had already begun.
They clashed with Kaido, who had always wanted to fight Golden Lion. They were soundly defeated, which made them realize that in the current New World, they couldn't survive without an absolute powerhouse as their leader.
As they pondered this problem, news reached them that the Colossal Battleship San Juan Wolf and the Pirate Empress Boa Hancock had joined the crew of Alucard, a former lone wolf.
Stragus and the others already had an inclination to ally with Alucard because of his past cooperation with their former captain.
But Alucard's image as a lone wolf was too deeply ingrained, so they hadn't approached him.
As soon as they heard that Alucard was gathering subordinates, they immediately entered the New World from the first half of the Grand Line, rushing over.
By chance, they heard the news that Alucard had started a war with Whitebeard. This made these pirates, who delighted in chaos, even more excited. This is perfect, they thought. If we can earn some battle merit by fighting the Whitebeard Pirates, Alucard will have no reason to refuse our request to join his crew, right?
With that thought, the remnants of the Golden Lion Pirates fought with a killing fervor, their five ships exchanging cannon fire with Squard's pirate crews.
As the ships drew closer, both sides boarded the other's vessels and began to fight.
Marigold and the others glanced at the fierce battle on the sea and thought, 'I don't know who they are, but we've been saved.'
They had entered the world of piracy much later and didn't recognize Dr. Indigo or the other remnants of the Golden Lion's fleet.
Still, the fact that they had stopped Whitebeard's reinforcements from advancing was a huge help.
BOOM!!!
Suddenly, the sea once again was pulled into the air as if a table were being flipped. The surface of the sea was an uneven mess, a sight that would make any amateur pirate faint with fear.
Iron Mask Matthew swung his katana, skillfully grabbing the mast of a nearby ship with one hand. He laughed loudly, "Whitebeard's attacks are as terrifying as ever! It was the same when he fought with Captain Shiki back in the day! Wahahaha!"
Before the shockwaves subsided, Squard swung his great sword, and it clashed with Matthew's katana. With the deck at an angle, Squard was above and Matthew was below.
"You're Squard, captain of the Maelstrom Spider Pirates, under Whitebeard," Matthew said, a sinister grin forming under his iron mask. "I heard your crew was completely wiped out by Gold Roger, and you only started over by relying on Whitebeard, is that right?"
Squard's eyes went red with fury. "Shut up!"
This was the greatest pain of his life. He hated Gold Roger more than anyone, and he hated it when people brought up that topic!
Suddenly, the upper hand the Whitebeard Pirates had just gained was turned back by the arrival of the Golden Lion fleet's remnants.
Marco, dodging a punch from Wolf, frowned. "Hey, hey, this is getting more and more troublesome. Even the main forces of the former Flying Pirates have shown up."
"However, the longer this drags on, the more it favors the Whitebeard side. Whitebeard has twenty-eight pirate crews under him. Only four have arrived so far, and the other twenty-four are still on their way!"
Marco naturally understood this logic and shouted, "Everyone, hang in there! The longer we fight, the more we're guaranteed to win!"
"Ohoho~"
Wolf let out a strange cry and spit out a mouthful of seawater like a bullet toward Marco. Marco dodged it repeatedly. Wolf scratched his chin, his voice mocking, "Says the guy who thinks you can hold out."
Dozens of nautical miles away, on the isolated island where Alucard and Whitebeard were fighting.
After Whitebeard unleashed the Tremor-Tremor Fruit again, both sides were forced to create distance once more.
Alucard looked in the direction of Hancock and the others, sensing that a large-scale battle was taking place there.
"It's nice to have a multi-person battle like this once in a while, isn't it?" Alucard said with a smile.
Whitebeard's Observation Haki could also sense the intense killing intent from that direction. He narrowed his eyes at Alucard, his deep voice unable to hide his anger. "My sons haven't fought in a long time."
"All the better," Alucard chuckled softly. "I'm helping them loosen up their stiff bones. You should thank me for it, shouldn't you?"