Ascians tend to favour enabling man to carry out its own evils and working through proxies. Remember in Haukke Manor they pretty much say they just showed Amandine the way. She was the one who chose to walk that path. The Ascians rarely seem to directly intercede, rather they work usually through proxy.

For this reason I think its highly likely both the Fall of Allag and the War of the Magi are things they had hands in. They didn't necessarily cause the events directly. They just nurtured the seeds that lead to it. Apart from opposing us, I don't think we have one example of the Ascians directly causing conflict. Rather they simply set it up, enable those who's desires fit the direction they want things to go and let human nature play out.