I'm curious, I assumed that I'd be able to throw enough runes at him in the Forge to grab him, but it seems neither him nor his recolor are available, did I just grab the wrong end of the stick there? Beyond that how do I go about grabbing him?
If you didn't get the Limited version of Dugon you're out of luck. Legendary (white, reskin) can be obtained like any other legendary, random chance through packs.