The Manifest Path/Nature of the Gods
There are several types of beings in the universe. For the moment, we are not concerned with the lesser types, and humans are covered elsewhere. The non-human abominations will also be covered elsewhere.
This leaves us with those of divine (or some might say infernal) origin. I would submit that while there are certainly differences in how one deals with those of divine or infernal origin, that they are the same in basic type, just as humans can be saintly or twistedly evil while still being of the same type. But within these divine beings we call gods is one further division: Those who can (or will) manifest in our world, and those who cannot or will not.
The Manifest Path in general does not concern itself with the latter, as while at least some of them undoubtedly influence our world indirectly, they do not aid us greatly in the long war with the abominations, nor do they harm us as the other gods do. As to what causes this delineation, one of the more common theories is that those gods with power too great to use it without risking the destruction of the world are bound by some pact not to do so. This seems reasonable enough, and thus those that do enter our world are either limiting themselves or are inherently less powerful than the other gods.
But what is their purpose? To put it simply, domination. Humanity dominates most of the known world, with the blighted lands of Beluaterra and the wilds that fill much of Dwilight being the only exceptions. These lesser gods with their abomination followers seek to change that.
Whether they are in the most objective sense evil is hard to say. Certainly we wish to dominate all lands that we see, and it is only natural that other creations do so as well. However, as we are also human, there is little point in objectivity. The abominations and lesser deities wish to climb to power over our broken lands, and we will not allow that. We were created (as, I suspect, were all other sentients) with free will and we shall not subordinate that to Arcane, Summoner, or any other bent on destroying us. That is the true purpose of our Path, to ready ourselves to win the war for domination of our world.