SPOILERS!!11!!?? ( but it's been more than a year since game's release!!)
Don't know what to think of Demise, the lack of backstory and origin other than: I'm a bad guy, deal with it gwahahaha! and his relationship with Ganondorf is what takes me off...
Maybe if they had explained more the conflict between Hylia and him and the previous war in SS, but meh. It kinds of destroy everything they've built up with Ganondorf so far. And that lead to a bigger problem with it, IMO Ocarina of Time should' ve been first in the series, for various reasons (and good ones I think) I should explain later.
I know Mangas are not canon, but the manga that comes with Hyrule Historia should've been included as a cinematic, or flashback or something. It almost makes sense after reading it.
Still, it is pretty badass, cool design, first time I saw him I was like: oh, sh"t! ,so I tried to capture that in this quick painting.
I was going to paint the battle second phase with the lightning and stuff, but I decided I wanted to use warm colors for this one.
Hope you like it.
What I love about Demise is that how he respects Link. As Demise mentions how other humans coward in fear in his presence, Link just stands there blade in hand ready to fight. And because Demise is impressed with Link's courage, he creates an arena for a 1v1 battle. It's just a very, very badass moment.