What do you think of a seer of void, knowing things not to do to keep the session up? And so, guide other by letting them know what they shouldn't do, rather than what they should do. (Or maybe it's a seer of doom thing? If yes, how can a seer of void guide others?)

A Seer of Doom would fit that much better- This is one of these cases where people assume the opposite must be true with a complementary Aspect. Light shows the Alpha, Fated, Proper Way, but that doesn’t mean because of that, Void must show the Improper, Bad Way. Rather, they’d know information Irrelevant to the Alphaness of the Timeline, not necessarily anything ‘bad’ or ‘good’ but just things that don’t influence it. Now a Seer of Doom? They’d be able to know what would make people and Timelines ‘doomed’.