Brook, a pirate originally from West Blue, who ate the Yomi Yomi no MI, was once a member and later the captain of the Rumbar Pirates. While sailing in West Blue, a young whale came upon their ship. Seeing the whale was sad, Brook suggested to Captain Yorki, that they play a song. The crew gave the young whale the name Laboon. Upon getting ready for the trip to the Grand Line, the Rumbar Pirates decided it was best to leave Laboon behind in West Blue, because of the dangers that awaited them. 
After crossing Reverse Mountain, the Rumbar Pirates, found Laboon right behind them. Due to the damages their ship sustained when crossing Reverse Mountain, the Rumbar Pirates docked at the Twin Capes. There they carried on singing and dancing with Laboon. When the repairs were finished they made a deal with Laboon. Laboon would stay behind and when they had sailed around the world they would take Laboon on their adventures.  After Captain Yorki and some other crew members fell ill to an incurable disease, Brook became the new captain of the Rumbar Pirates. Through his adventures, he earned himself a 33,000,000 bounty. After venturing into the Florian Triangle the Rumbar Pirates were attacked; only a few including Brook survived. However because their attackers poisoned their weapons and the ship doctor had been killed, they all slowly succumbed to the poison and died. Yet they managed to play one final song for Laboon; which Brook recorded on the Tone Dial.  Thanks to the Yomi Yomi no Mi (Revive Revive Fruit), Brooks soul was able to have a second life. Although due to the thick fog in the Florian Triangle, it took Brook 1 year to find his body. He then spent the next 50 years on the ship, unable to escape the Florian Triangle because the rudder was broken. Roughly 5 years before the start of the series, his ship came upon Thriller Bark where his shadow was taken by Moria.