Official reason?

It's the official battle dress for the Kingdom of Lucis, and each of his comrades wear their variations 

"In the Kingdom of Lucis where our heroes reside, the colour black has historically been treated as a special colour. Because of this, the attire of the royal family and those in occupations closely tied to them are unified by having black as a base colouring."

"This part of the lore is the reason why the outfits of all four main characters are black. For the finished game we also intend on having their clothing having effects in battle and not just being a part of the world and its background."

 

Zere ya go. 

source

 http://www.eurogamer.net/articles/2015-10-23-square-enix-explains-why-final-fantasy-15s-main-characters-all-wear-black 

 

The colour black also has an association with death in some cultures...I wonder if thats got something to do with the colour of choice of the Kingdom Lucis too?

 

Or maybe, they wear black because they want to appear as 'stars in the night sky' - recall that Lucis is Latin for light, and so the defenders of the kingdom must shine brightly amidst the dark sky (hence the choice for Black as clothing). Either that or the predecessors of the Lucis kingdom were goths.

 

Is Etro, the goddess of Death still in this game? Or was she removed during the conversion from FFvsXIII to FFXV? I know Stella is gone.

I thought it would have something to do with Organization XIII. I guess not.

Or you know, because black = heavy and edgy. I'm fine with that kind of style and genre, and even I know how cliched that is. I still like it though.

The colour black also has an association with death in some cultures...I wonder if thats got something to do with the colour of choice of the Kingdom Lucis too?

 

Or maybe, they wear black because they want to appear as 'stars in the night sky' - recall that Lucis is Latin for light, and so the defenders of the kingdom must shine brightly amidst the dark sky (hence the choice for Black as clothing). Either that or the predecessors of the Lucis kingdom were goths.

 

Is Etro, the goddess of Death still in this game? Or was she removed during the conversion from FFvsXIII to FFXV? I know Stella is gone.

Etro still plays a role in the game. Noct and Lunafreya have abilities associated with Etro (sensing the dead, oracle respectively)

The official response is that the colour is special to the Kingdom of Lucis and so, the royal family wear that colour. So there ya go. It's not because they are a failed J-Pop band (plot twist).

Real reason: aesthetics. 

 

Real reason: aesthetics.

But seriously, the colour black and the clothing has to do with the lore of the game. The clothing will have a lot more function in the final game. Black, as stated before, is a historically special colour for the Kingdom of Lucis.

 

 

I thought it would have something to do with Organization XIII. I guess not.

I think that's either a joke or not. But if not, FFXV and Kingdom Hearts lore aren't connected.

i figured it was just another case of "rule of cool"

Wow that's fascinating. Who knew?

Na, it's because they are somehow involved with the Organization.

No it is like the lost story that was a great game too.

 

That's pretty badass when you think about it, because right there, we're already witnessing snippets of the lore that Final Fantasy XV is sure to be rich of!  That's pretty cool, if you ask me!

 

Plus, black is a badass color, so they are rocking it!