Arn is a zealot to the Goddess Chaos. This can be attributed to the unfair treatment that hybrid races, such as himself, recieve from the Lhumaeo, and the fact he was abused horribly by the household he once live in. In order to find his own form of solace from cruelty, he turned to Ebonn Lord worship in spite of the Star Deities.
So why did he choose Chaos?
She is the embodiment of pure, unhindered, chaotic power. This lets her bend the very fabric of space around her, allows her to poison the minds of living creatures, and cause mass hallucinations and hysteria. In his weak position as a house servant, Arn wanted such power, and what better way for a mentally disturbed young man to attain a delicious vengeance to those that oppress him than to bring the most powerful of the Ebonn Lords.