First things first, we must return to the end of the collapse. During this part of the destiny universe; things weren't looking up for humanity. Our golden age was abruptly ended due to the darkness following the traveller. But it wasn't the only entity that wanted vendetta. The eliksni also wished for their great machine to return. The vex that were in the system being studied by Dr.Shim and his colleagues in the ishtar collective went rouge due to the presence of the darkness corrupting them (and them subsequently corrupting the darkness). The cabal found themselves in our system after running from... something... and small hive activity began on the moon The traveller lost hope. It (or what could be controlling it) decided to once again flee the inevitable. And that is where things changed. Rasputin knew to maintain his directives, the traveller had to stay. The only way to stop it was to fatally damage. And so he did, sending golden age warheads at the bottom of the travellers's chassis. Unable to leave; it released a super nova of light energy. This birthed the ghosts, turned those humans who attempted to leave in fleet ships into awoken, and sprawled the forces of darkness. [spoiler]considering these intervals, it's possible that a fragment of the traveller somehow landed on the moon[/spoiler] Fast forward a few centuries ... Or ... maybe millennia? The timeline isn't too keen with dates - ANYWAY! The city was victorious against the eliksni attempting to retrieve their great machine during the battle six fronts, and twilight gap. So pleased, and confidant in themselves; they decided to finally answer to the hive dilemma on Luna... how foolish they were They refused to listen to the admonishments of Toland, most knowledgeable on hive arcana. Even when the trusted crucible founder, and pupil to saladin, shaxx forbade them; their hubris disobeyed. Thus began the battle of Mara Imbrium, more commonly known as the great disaster. Here; Crota was summoned and decimated guardian forces. Due to him not being in a throne room; he was unstoppable. Thousands of guardians fell to his blade. possibly in the hundred thousands. All but one of the praxic fire was extinguished. And even the great titan, wei ning fell. Beaten, we'd retracted all duties and forces from the moon. It is possible that during Crota's excursion during the disaster, the wizards obtained that shard. We know through numerous guardians such as dredgen yor that light could be corrupted. Perhaps they were attempting to simply destroy the traveller... Or perhaps they wished to corrupt it, corrupt us! Meh, doesn't matter we beat that mission years ago! No way they'd glean any info from it that they might be utilizing! ESPECIALLY considering the traveller is the reason the proto hive made their symbiosis with the worms. AND we killed two of their gods, have taken the osmium throne, and it's not like Savathûn or someone isn't gonna want some revenge!

I don't know, but I'd bang the Siphon Witches guarding it.

If you didn't notice the Traveler is missing a lot of pieces. They had to end up somewhere so they probably found it. It's more mysterious as to how a discarded piece of the Traveler could be used to hurt it after it's already been detached. That's some voodoo magic.

Best not to think about it, Bungie sure as shit didn't.

"A thousand years ago, this land was green and good - until the Crystal cracked. For a single piece was lost; a shard of the Crystal. Then strife began, and two new races appeared: the cruel Skeksis, the gentle Mystics. Here in the castle of the Crystal, the Skeksis took control. Now the Skeksis gather in the sacred chamber, where the Crystal hangs above a shaft of air and fire. The Skeksis with their hard and twisted bodies, their harsh and twisted wills. For a thousand years they have ruled, yet now there are only ten. A dying race, ruled by a dying emperor, imprisoned within themselves in a dying land." Someone at Bungie really likes the Dark Crystal.

When the Traveler saw the darkness coming it tried to flee. Rasputin saw the Traveler doing so and opened fire on the Traveler until the Traveler stopped and went into a hibernation kind of state. Rasputin did so because it saw the outcome of the Traveler leaving us by running his infinite simulations and calculations an we would be destroyed by the darkness. During this attack pieces were detached and sent to the ground in various places which is where I assume the Hive got a piece from. Moments before the Traveler went into its hibernation it sent out a bunch of other pieces of itself in a focused form of light known as ghosts. To aid in the fight against the darkness. I believe it wasn't as much as choosing us as it's guardians as it was a self defensive move. The Traveler is incapacitated and unable to either flee or defend itself so it armed us with the capabilities to do so until it has healed enough to leave its hibernation and do whatever the Travelers next move is. Whatever that may be. Hopefully it isn't too mad at Rasputin haha.

The hive have hunted the traveller for eons dear, they would have gotten shards over the years dear