The Rumbar a pirate crew from West Blue, long dead. They were first mentioned by Crocus as the group of pirates who brought Laboon to the Twin Capes.
50 years before the start of the main plot, the Rumbar Pirates were traveling in the West Blue. One day they found a baby whale following them. Seeing that he was lonely and sad, they decided to play him some music to cheer him up. The next day they thought he was gone, but they found him. Seeing that he was still following them, they decided to play some music for him and this time let him follow them, because he was very cute. While giving him bait, they discovered that Brook had called him Laboon.
The strength of the crew took them far into the Grand Line, where they experienced its cruel seas and unpredictable weather. Days passed, and at some point, after emerging from a certain forest, Yorki, their captain, and several of the crew members had contracted an incurable disease. Deciding that no one else should be infected, Yorki wandered off with the sick crew members on their ship and hoped to pass through Calm Belt. That’s when most of them died.
However, the Rumbar’s crew met their end by entering Florian’s Triangle. Much of the crew survived the attack, albeit narrowly, but as the enemy had contaminated their weapons with poison and the Rumbar’s doctor was killed in the attack, the survivors were slowly dying. Knowing he ate the Yomi Yomi no Mi, Brook suggested his crew play one last song which would be recorded on a Tone Dial which they had previously purchased from a merchant. As it would come back to life after its death, Brook promised them to take the dial and play it so Laboon could hear it. Delighted with Brook’s proposal, the remaining Rumbar crew members gathered what little strength they had and began to play their favorite song for the last time.
Although happy to have recorded their song, the remaining Rumbar Pirates slowly succumbed to the poison and died one after another. They all fell, smiling, until only Brook was left alone. With a heavy heart, Brook continued to play alone until he too succumbed to the poison and died.
After a year of searching, Brook’s soul found the Rumbar and his body, which had decayed into bone. Resurrected in skeletal form, Brook put the remains of his comrades in coffins. However, Brook still remained aware of his crew’s inability to fulfill their promise to Laboon.
The first ship used by the Rumbar’s crew was relatively normal sized and debuted in a flashback in Chapter 103 and Episode 63. It featured the bull’s skull of the Jolly Roger as its figurehead (at the originally, in the manga and anime, the figurehead was without a man).
The second ship used by the crew after losing half of their crew debuted when Brook himself used it to sail around Florian’s Triangle.
Although they were wiped out roughly half a century ago, the Marines have retained information on the crew, as they have managed to trace Brook’s ties based on old bounty posters.