Gluttony
The passage to the Alpha Universe triggered a chain reaction inside the Prima Universe, making more and more mind-blowing events come to be. It was like the Universe Will pushed its children to thrive beyond their limits, fight for what they desired, and have a chance of eternal glory.
The most meaningful of all was the rise of a new super-race, the Supernova Race. They rose to fame fifty years after the arrival of the entity known as Flame Imperator and made their grand entrance by reclaiming the world that was once theirs and erasing a Rank 9 Archangel from existence.
Of course, the death of an Eternal Detachment existence from the Heavenly Race infuriated the Archangel Primarch. Still, by the time she and the rest of her race's powerhouses reached Solaris, the Supernova Race had already fortified the entire world.