Galaktikon isn't exactly the same, it's a different theme. In the words of Brendon Small, 'the album follows a super hero who has just gone through a "very messy, public, intergalactic divorce," but his ex-wife gets kidnapped, so he attempts to rescue her only to find out that she is dating the antagonist', so it's not Dethklok but with Gene and Bryan in the band it is pretty much the Dethklok band.
There could have been legal reasons why the band stopped, Brendon never really explained it. But he did create Metalocalypse so I would imagine he also created the band and the name.