I have a theory that the Traveler is Evil to backup my theory, The Darkness follows the Traveler where ever it goes, also I think the Traveler is a Beacon for the Darkness.
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This theory just shows you don't read the lore dear. The darkness wants to destroy the traveller, it sets its minions after it. And the traveller isn't evil, but isn't good. It wants balance in the universe, but knows others have to die before it when times get rough.