Alright, so we have the speaker. Seems like a nice chap, right? Wrong. He wears a helmet. Why would he wear a helmet? He's dehumanized for a reason with this helmet. Therefore, he must be a villain since people don't wear helmets in the tower, showing that the tower denizens are not evil. But the speaker wears his helmet, making him a dehumanized evil guy. He has a lot of power and power corrupts, and absolute power corrupts absolutely. He has all this pull, this power, this ability to represent the Traveler. Well, what if the Traveler's dead? That would be a kick in your morale, no? All we know is the Traveler is incapacitated, and the Speaker has a vested interest in exploiting this for his own personal gain. He most certainly doesn't work for the Darkness, but rather for his own advancement, in which the Last City and its Guardians are pawns in his plan to save humanity and become its God Emperor, utilizing the power of the Traveler to make himself ascendant. In the meantime, he fills your head with half-truths, not lying to you since that would be most unethical. As Guardians, you don't need to know the truth. Be happy in your station. He also may have placed the purple balls in the tower to distract and confuse Guardians, but this part is mere speculation. It's also possible that the Cryptarch is helping him accumulate enough glimmer to utilize to take control of the Traveler, but that's not very probable. I do not apologize for slandering the purple ball. In the end, the Speaker is on our side, hoping to renew humanity under the guidance of a human and not a mysterious sphere whom we do not exactly know the intentions of. He's lying to you for your own good, and for the good of every man woman, and child. EDIT: He's not evil in that he's screwing you over. He's just screwing the Traveler over by replacing it as your new God Emperor. If you want "working for the Darkness evil", there's the Cryptarch.