Archo - Form

A hyperintelligent, god-like post-machine 'species' with no physical body. Archo - forms are immensely powerful, and they are what caused the starsong.
The signal, when it is seen by an individual, will cause them to rapidly self-evolve into a young archo - form. It then causes an immense shockwave in the universe, creating the lifeform energy barrier and absorb the souls of all sentient beings in the Fortrais Galaxy Cluster into itself, causing them to obliterate and disintegrating all physical lifeforms for energy, effectively eating them. This causes the young archo - form to grow to an immense size. As it matures, it may emit more starsongs at nearby galaxy clusters as this is how they reproduce. All starsongs went silent, though, as all archo-forms eventually ascended and left the universe in search for a different universe to reproduce in.
The immense power of this species is put into perspective of how easily it has destroyed all precursors of the Fortrais galaxy cluster. There is no method by which archo - forms can be discovered. Not even the precursors knew about the cause of the lifeform energy barrier and even the Pyre of Stars's attempts to see the past are somehow shrouded by the Fortrais Archo - Form's precognion jamming. It kept itself unknowable.