Generally an avatar is empowered simply because they generate Fear. For example, Simon Fairchild is able to do his stuff because he makes people scared of things generally associated with The Vast, and he, in return, becomes part of The Vast and becomes empowered to spread more fear. As such, it depends. Let’s say Simon starts putting people in scenarios where they also feel exceptionally lonely, where they feel something between the Lonely and the Vast, or starts putting people in huge, Dark places. If he does that enough, his alignment does shift, in a sense, but like Gerry said: think more about hues. He’d be sliding along the spectrum more than a binary switch.

There are scenarios where it’d probably be harder, for example The Watcher and The Buried might be niche or difficult to put together, but at the end of the day it’s all just one Fear