Like his wife, Aino, he was once benevolent, fair, just and wise, however, his mind was polluted by the chaotic toxins placed in the water, thus turning him mad. His madness led him to plan a religious sacrifice of Queen Aino to the Undine gods, in order to purify the waters of Aquis. Adaro is not inherently chaotic, nor evil, therefore does not ally himself with Abaddon, instead he is misguided in his judgements, being used as a tool by the chaotic god.
Jen fights against him and kills him in order to restore the balance to Aquis.