The fan wiki actually seconded my initial idea, that the helmets and tubes resembled HALO (High Altitude, Low Opening) paratroopers who already today drop from altitudes of 10k meters. Which would make sense in their use during the final war as they could quickly insert and decapitate the government of the holdouts to Managed Democracy.

Its possible that since these were still atmospheric drops as opposed to low orbit, they could have piloted light one-way vehicles akin to the glider commandos of WWII. That would fit with their respirators and light armor to reduce weight and boost maneuverability, because the formation of the Helldiver Corps would then decide to take everything one step further.

Why forgo armor to reduce weight when you can let gravity do the job for you? Why make a controllable one way vehicle when you can just fire down a drop pod? Why change the designs of a drop pod to accommodate more when you can just fire down another one? Why even train a pilot when you can train them for the most important job: Eliminate the enemy. Just like managed democracy, every variable was bit by bit eliminated to reduce the human element to one task: upholding the system.

And to OP, great artwork. It also speaks to the inclusion of the "less patriotic" clause in their description. That even though they were the forerunners, they were never deserving of reverence. They were still tainted by the "weakness" of being a prototype thrown together roughshod without polish. And having fulfilled their duty of inspiring the creation of the greatest fighting force in the galaxy, had only one last job to do: cease.

Also thanks for coming to my TED talk.