Charko is Ébano's tar-horse. Along with Ébano and Amadeus, he made it through the Calamity. While somewhat more intelligent than an average horse, he cannot speak. Charko responds to the winged rat's command just as faithfully as he would Ébano's.
His body constantly drips tar, but the drops of tar follow him and melt back into him as he walks. He does not need food or water to stay alive. The nature of his soul or whether he has one is not understood, but Charko is not a creation of the Earth Dragon, and is not “alive" in the usual sense of the word.
He is able to cool and harden certain portions of his body at will, making it safe for his master to ride him without a saddle.