Yes, absolutely! In the beloved anime series 'One Piece', Ace is indeed the brother of Luffy. Let's delve into this a bit, shall we? They aren't biological siblings, though. They share a bond thicker than blood, formed by their shared experiences and unyielding loyalty to each other. Born as Portgas D. Ace, Ace is actually the son of the Pirate King, Gol D. Roger. However, he was adopted by Monkey D. Garp, who is Luffy's grandfather, making their relationship a bit twisty, yet fascinating.
There's also a third brother in the mix - Sabo. Together, these three made a pact to become pirates when they were just little tykes and considered each other brothers ever since. Sadly, Ace met an untimely end trying to protect his brother from the Navy during the Marineford War, one of the series' most poignant moments that left us fans teary-eyed. This event significantly impacts Luffy, propelling him to train harder to protect his remaining family and friends.