Aoskar

Aoskar is a fictional entity, a greater deity in the Dungeons & Dragons Planescape campaign setting.

Aoskar, God of Portals once used to reside in Sigil (naturally, as was the City of Doors). Eventually residents of the city turned to his worship and he became the most-worshipped god Sigil had ever seen. So much that people started to neglect the Lady of Pain, their old ruler.

The Lady did nothing until finally one of her own servants, a dabus (now known as "Fell") proclaimed himself a cleric of Aoskar.

The Lady didn't wait anymore. Aoskar was killed, his temple was destroyed (later rebuilt somewhat and used as the Athar's headquarters), and the Lady decreed that anyone who so much as mentioned him would pay dearly.

Thus, since then, the Harmonium arrested any who so much as spoke his cursed name, burned anything with his image, and outlawed any reference to the God of Portals. Those who mention him are LUCKY if they are arrested - if they aren't, the Lady might get them.