December 17 Update

[Rakurai]

It's referred to as an "ancient Kuronite titan", so I'd assume it's a Kuronian.

The fact that it seems to have been mass cloned by Double gives some reason for it potentially being classified as a Darker, though.

[strikerhunter]

Come to think of it, did they mention what Magatsu's race is? Darker or Kuronian?

They mentioned a while back that Magatsu is a Dark God of Destruction that was sealed away. It was sealed away but is now freed when that seal wasn't recharged.........(someone forgot to do her work <_< ) So it's most likely a Kuronian but could have affiliation with Darkers.

[LonelyGaruga]

It's a Kuronian.

Of note, the mobs summoned by it are palette swapped kuronians (I saw tree wielding oni and the paper tag ghosts, probably were others) that share the same color scheme and light weakness.

[Hrith]

Looks like a Halcotan monster to me, especially considering what Ep3 ch3 said about it.

[Selphea]

Bah I need Light Demon Hunters :/ Or maybe I should just make a generic Discerning Eye/Strategic Stance/Perfect Calamity weapon to cover Anga too.

[Dycize]

They mentioned a while back that Magatsu is a Dark God of Destruction that was sealed away. It was sealed away but is now freed when that seal wasn't recharged.........(someone forgot to do her work <_< ) So it's most likely a Kuronian but could have affiliation with Darkers.

About your spoilered part.
It's exactly what we do in the latest story mission actually. The parallels to Dark Falz are also brought up (ie : ancient evil of destruction sealed up on a planet).