Except we totally made those names up, they didn't come by and go " yeah we're the hive and we're total royalty, see I'm a knight!!" Their names literally fit what they are Dreg- Worthless, usually seen lowest of the low. They fight in the front as grunts with no armor and generally bad weapons. Shank- this word has multiple definitions as either a driving force or something that provides support. We see shanks clustered in the front line with dregs and they will usually push forward or hang around dregs. Vandal- the definitions are literally destroyers / defaced of stuff. This is the only definition that doesn't fit as the vandals are more deadly and more coordinated than dregs, but do not seem to do much else. Servitor - is just a servant and this is seen by them buffing other Fallen. Captain - just a leader of a unit. Also the cabals names all reference military aspects in terms of a legion. And with the hive thrall is a forced servant and the acolytes are just servants of their God. I could continue this list, but I'm on my phone and you get my idea.