There will probably be a mini boss fallen captain similar to Aksor probably a new House of Wolves Kell (since The Queen killed the last one) probably have some tough shields similar to a public event Reaver Captain and then it will probably be a huge Servitor as the main boss with no crits spots and some weird way to beat it or lower its shields maybe it even self recovers and gains health back. Since when you fight Sepiks Prime he seems to be absorbing energy when you walk in on him maybe it gains health/power that way. Also as a raid encounter/part you have to fight 6+ Devil Walkers.