Described as a black shadow against the night that eclipses the stars, Charsaug possesses scales so dark that mortals can only see him in daylight or when highlighted by a wash of lava, into which the dragon frequently plunges.
Charsaug was not spawned by the Dragonfather Toruk. His sire was Erdross, a dragon who made his lair in the Suneater Mountains and came into contact with the giants of Bemoth, and who participated in the alliance of dragons organised by Blighterghast in 1000 BR to drive Toruk off mainland Immoren. Eventually the giants endured great sacrifice to defeat Erdross, but they only succeeded in splitting his athanc in two and threw the shards into a volcano, from which Charsaug and his twin Ashnephos spawned.
The giants and the dragons have since warred for millennia. While the dragons have not yet gained the upper hand, they do slowly win this war as the number of giants thins and the dragons remain undiminished.
In 607 AR, Blighterghast calls all the dragons again, including Charsaug, not against Toruk, but against Everblight, one of the weakest dragons who has proven himself a dire threat to the rest of the dragons by taking control of the Nyss and consuming the athanc of his brother Pyromalfic.
During his journey to the lair of Blighterghast in the Wyrmwall Mountains, over the Silvertip Peaks in Rhul, Charsaug witnesses an army of blighted Nyss warlocks conducting a ritual which spawns four archangels - gargantuan spawn that bears a striking resemblance to the dragons themselves. Charsaug sets out to investigate, killing many blighted Nyss and and lesser spawn before the archangels engage in battle with him. The archangels manage to wound Charsaug, and unwilling to risk even the smallest chance of defeat, he decides to retreat southwest, settling in one of the few active volcanoes in the Wyrmwall alongside Ashnephos. However, Charsaug demands Blighterghast to have the archangels destroyed before he'd accept to join the alliance against Everblight.
Charsaug soon receives an emissary from Blighterghast - the blackclad Krueger the Stormlord. Krueger asks Charsaug to take part in his plan to insert draconic blight into Caen's ley lines. Charsaug feels insulted by Krueger, who apparently treats him as an equal, considers his plan meaningless and decides to kill Krueger and return to the east, but Ashnephos reminds him of the oath Erdross made with Blighterghast and the rest of the dragons sixteen centuries earlier. Charsaug explains to his twin that Blighterghast doesn't show trust by not explaining how this ritual could lure out Everblight, at which point Ashnephos asks Krueger who answers that Everblight has learnt to divide his athanc without dividing himself, and his plan will allow the dragons to locate all of the separate parts of Everblight's athanc, and then capture and consume them. Ashnephos tells Charsaug Krueger is right, before both of them fly out of the volcano to occupied Llael to enact Krueger's plan.
However, once he senses the presence of Nidoboros' athanc on a Cygnaran convoy, Charsaug breaks away from the alliance's campaign against Everblight to run after the athanc. He chases the athanc to the city of Orven, with Ashnephos following shortly after. During their assault on the Cygnarans, Charsaug and Ashnephos attract the attention of Lord Toruk, who defeats and consumes Charsaug after a short fight.
Uniquely among dragons, Ashnephos and Charsaug seem willing to cooperate and live in relatively close proximity. Both seek to consume the other after the giants are defeated.
Charsaug, the more intelligent and reserved, but no less malevolent, of the dragon pair, seems obsessed with grander schemes and more wide reaching plans than simply destroying Bemoth and terminating the giants. The giants apparently have had less direct contact with Charsaug, although he has left his own bloody claw print on the peoples of Bemoth and relishes the opportunity to destroy any giant he finds vulnerable and exposed. They have observed Charsaug winging far from the Suneater Mountains, exploring many volcanoes of the north, and inspecting other ruins. He roams as far away as the southern Abyss, and scattered skorne records refer to this creature, though Charsaug has avoided conflict with the skorne, preferring to prey on the giants.
Charsaug seems to prefer to hunt nocturnally and moves less boldly than Ashnephos. He is seeking for a tool to use against Ashnephos when their alliance against the giants inevitably crumbles, though any such plans never got to fruition before Charsaug's death at the claws of Toruk.