Is this small passage clear and worded properly?

Is this small passage worded properly, particularly is the details of the bargain clear? FYI- Szass Tam is the lich. Meanwhile, Szass Tam summoned the evil god Bane, the Black Hand, by performing an intricate magical ritual that required him to sacrifice slaves, necromancers, and Pyras Autorian, the tharchion of the Thaymount. Szass Tam made a bargain with Bane in which the god agreed to provide the lich with his knowledge about the nature of magic in the aftermath of the Spellplague, grant him the ability to create more undead creatures, and augment his mystical strength. In exchange, Szass Tam promised that when he became the sole ruler of Thay, Bane would be the only god worshipped within the country, and that he would also surrender his soul to the Black Hand one thousand years after he had attained complete control of the nation.