My understanding comes from the book of sorrows (posting this prior to what I say, also to day without saying spoilers) The worm gods seem like a physical representation of the deep, which I believe is the darkness. And the traveler and leviathan directly opposed the deep. The ahamkara possessed similar descriptions to the worm gods, perhaps being another host to the worm gods or representation of the deep itself if not the same thing as the worms. Toland believes that the darkness is the final state, meaning the worm gods are either physical representations of that final state or direct servants. Were I to guess, near the end of their Destiny plans, our guardian learns of the sword logic and the darkness and the greater plan, possibly following in the dark footsteps of the three sisters, or possibly finding a remnant of Toland to direct them. That would make the leviathan, or possibly taox a great boss to battle, but through sword logic, the dark guardian could re-acclaim to the light. Thus the guardian would know some greater secretive info about both sides by that logic, and possibly defeat or forever halt the darkness, or perhaps even turn on the traveler.