Ashan, where is he from?

Ashan not only sounds better, but also logically ties into the plot: the goddess who created the world is named ASHA, so the world is ASHAN.

It's not a certainty, not a certainty... In some sources, the spider queen is indeed named ASHA (I tend to think that this is the correct version). Hence, ASHAN. Asha and Ashan were chosen precisely because of their pleasant sound. It's like sushi, sashimi, and Doshirak – because many people would find it unpleasant to try sushi, sashimi, and Doshirak.