In the seven years since then, a lot has changed with the army - a big chunk had to be sold, the 40k universe saw a big upheaval and Primaris Space Marines became a thing.
So in the era of the Great Rift, the Rainbow Warriors also saw a similar upheaval, with a new Chapter Master ascending: Kaine, the Argent King
Now clad in a suit of Terminator armour, Kaine has traded his power sword for a thunderhammer and storm shield, and is a much more grizzled veteran. He lost his left eye during the Blood Star campaign, that also saw the death of the previous Chapter Master.
Now he leads the Rainbow Warriors in their efforts to defend the worlds of the Imperium Nihilus
Until next time,
Retconned Legion