If I had to guess, I would say, judging by the "Space Magic" power granted by the Traveller, it could have released an energy shockwave from its position that goes right through Humans harmlessly, yet eviscerates Fallen, Hive, Vex, whatever was attacking at the time. And communication, judging by the Traveller's evident power, would most likely be telepathic. Obviously this is all speculation on my part, so I have an equal chance of being right or wrong.