It'll be the Kell/Archon we don't defeat in the last story mission. We will first kill the Archon (which I believe is second in command) in the early checkpoints of the raid. Maybe some random shit with massive shanks with thousands of rockets or a flying platforms of sniper vandals. The final boss will be the Wolf Kell. The strike revolves around super walkers, so no new boss their. What I'm interested in is Fallen command. The House of Winters Prime servitor was killed "long thought dead", so the Kell is in charge of them. The Devils have Sepiks in charge. The Archon Priest we fight in Venus is indirectly labeled as HoW, but as we all well know, we rainbow burned the -blam!- out of him. So chain of command? Who knows. This is based off the strange info we have AND the descriptions of the HoW raid armor in the files