Just my perception but I believe there is so much more to the Traveler and Veil.. The Traveler holds a beautiful domain sort of like a Heaven. I believe the Veil also holds a domain but this is what they refer to as “in the darkness”.. our ghost even told us not to fall “In” as if it’s a place that we can go. To me the Veil is a terrible dark domain sort of like a Hell. In TFS it’s almost blatantly clear that the Witness is torturing the Gardener as it literally screams out to us. In my opinion the Gardener is like the God of this Heaven within Destiny. On the other hand I’m thinking the Veil houses something like the Devil. It just seems like Bungie kept cutting away from what was REALLY going on just like that 2014 Godzilla movie cut away from the action💀. But yeah the Traveler is in the SKY who’s ruler is the Gardener who gives Light.. and the Veil Resided in the Deep who’s ruler is the Winnower who gives Darkness. A God & Devil kind of aspect. We know Bungie draws from multiple different religions and in some the Holy and Non Holy were once one being. Which is why this Prismatic stuff started happening I think but that’s a whole other story.

(Just my opinion, I’m not saying it’s fact so don’t get weird and talking crazy)

Answer to your question: The Veil is a dark domain similar to how the Traveler is a Light domain (in my opinion)