Whoever wrote this story should feel absolutely ashamed of themselves. I know they probably don’t care because they get paid either way, but this is one of the worst bits of storytelling in any medium across any platform in any time period of human history. Nothing is explained, everything is rushed and the new characters are some of the worst ever produced by this 3 billion dollar company. This all comes after the previous writing team made WQ from their homes during a pandemic and with far less money and resources. Absolutely shameful that 3 billion extra in resources and working in your huge studio produced worst quality content than a team working from home. What makes anyone want to pick up the Final Shape when the climax to that moment has been destroyed by missed opportunities to set up the narrative? This is D1 vanilla level negligence to a narrative, clearly showing your lack of respect for your long term audience.

A power source basically. Unfortunately the game is terrible about explaining this.

https://www.bungie.net/en/Forum/Post/262561396/0/0

Bungie don't have an idea. It's just a word that sounded mysterious and cool. They will think some excuse to this but I wouldn't expect anything good.

Unfortunately, no one else really knows for sure either. So far all we've been able to piece together is that the veil was required for the witness to open the "portal" thing on the traveler. We know that it reminds ghost of the traveler. And we know that only objects of paracausal nature can form the link (the radial mast allegedly and of course our ghost). The actual origin of the veil is completely unknown. We don't know if it was created by the traveler, the witness, the Ishtar collective, or something else. We also won't truly know it's function until it becomes clear what the witness did with the traveler. Bungie did mention in a twab that we would get a mission (dungeon?) Next season that provides some insight to the veil. The only other info we have on this mission is that osiris is involved and that one of the rewards is a large hand cannon with a scope on it. I'm hopeful that it provides some context as to why the witness needed the veil and particularly where it came from. Guess we'll have to wait and see.

The Veil is a vessel, an object, a place, call it what you will, where Light and Dark are used both together in tandem to create, to destroy, to create portals etc. That’s why our Ghost said it feels so similar to the Traveler, because it is an area concentrated with full Light.

That will be answered through the seasons.. sounds like specifically next season At the end of the campaign… ikora tasks us to answer this question

Destiny community: "Bungie what is the veil?" Bumgie: "Yes"

Nobody has a definite idea so far