He was the very first Elder Dragon we would ever come to see in GW1 and his presence has been described in a book and is seen in-game. His size and appearance is terrifying. His powers seems endless.
Path of Fire (before LWS4) showed us the weakness of this great beast: the Dragonsblood Spear. We destroyed this, however research from Yasna of Kralkatite ore during LWS4 Episode 1 at the Astralarium hinted that confluence of astral energy (aka intense focused light) could purify the Kralkatite. Fast forward even further to LWS4 Episode 4 and we learn that the Djinns' have magic protection capable of resisting the Brand, something Ziya grants the Commander from arcane experiments on corrupted sand.
So we went from one sole weakness to Kralk and his Dragonbrand, to potentially three ways we can defeat him? Granted, the magic the djinn's wield is protection based, but I'm sure Taimi could find a way to turn that into a weapon. Especially if you combine it djinn's protective magic with the other two - intense focused light and dragonsblood weapons.
My question is, where does the destinction lie between the Brand and Kralk himself? The Brand is his corruption, but is it also a part of him? For instance, is the Brand also part of his thick hide, his internal structure, or does it extend beyond that and is far more vital for his survival?