Well, okay, the way I understand it, Dunkelzahn didn't exactly get offed the way it sounds. He basically did what he did to slow down or halt the impending return of lovecraftian horrorterrors from the places between the stars, and handed out the magic items to make sure some people who needed them for the upcoming battle against the horrorterrors would have them... or at least, that the items would be in a position to end up in the right hands.
Most of the dragons seem to have the common goal of dealing with the horrorterrors, but don't get the idea that the dragons are remotely altruistic. Some of them like to play 'champions of metahumanity' but at the end of the day, like everything else with the smallest modicum of power in the 6th world, they've got their own agendas, and often times their own menus. Look who is on the menu! (Hint: Dragons don't really do vegan diets.)