Spade Pirates

The Spade Pirates (スペード海賊団, Supēdo Kaizokudan) is the former pirate crew of Portgas D. Ace that was founded two years before the current storyline.

History
After Ace was defeated in a battle against Whitebeard and asked to join Whitebeard's crew, the rest of the Spade pirates tried to take Ace back. They were all defeated in their attempt to get their captain back. However, they were fortunately spared and taken aboard. They have since then been integrated along with their captain into the ranks of their former enemy.

Crew Strength
The Spade Pirates were powerful enough to make it through the Grand Line. Their captain, Ace, managed to fight in terms of equal to Shichibukai Jinbei, as well as being offered a position as a Shichibukai himself. The crew also showed a lack of fear, as they attempted to attack Whitebeard in order to save their captain.

Trivia

 * Their name "Spade", as well as their captain's name "Ace", are both references to the spadille.
 * There is a belif that they are actually Alies of White Beard, following under the 1st mate but still accept Ace as their captian.