the initial "D" is one of One Piece biggest mystery we have yet to learn about.
with Luffy's Grandpa and Dad, known "D" are also Gol D Roger his son Ace and his wife. Marshall D Teach, the one who captured Ace. that Gigant named Jaguar D Saul who helped Robin when she was a kid and now Law is also a D. I am so excited what Corason will say next chapter :D
I don't think the people who share the D in their name are related by blood.
Since there's Jaguar who is a giant and all. But I think that, maybe in the past, this group of people came together to form a "family" and shared this 'D' in their names.
Lol the D is still a mystery. The only thing common is that the holders of will of D tend to be the people who made a big change in the world. Theyre capable of doing big things. And no theyre not related by blood.
No they are not related by blood cuz even the awful blackbeard teach has D in his name. And upto now he is the only D afraid of dying.
so d as in celestial dragon or d as in dragon, luffy'sdad dad? Or is it all the same?
Cuz there's gol d. Roger, and then luffy'sdad dad, monkey d. luffy. At first I though ooh are law and luffy related somehow? But I guess laws family was a celestial dragon then? Dammittt I ant the nx chapter