What Will Happen When the Astartes Arrive in the Spirit Cage?

What will happen when the Astartes come to the spirit cage? The chain sword slashes the Devouring Beast? Bolter top lane lighthouse? Waking up from the apocalypse, Chen Zhao, codename: GA-13, captain of the original Blood Phoenix Chapter, discovered after his death that he did not return to the Golden Throne, but traveled through time again, coming to a world full of flesh and earth, and his body returned to before transformation. Fortunately, the Holy Ark of the second life came with him, not only providing him with nano-armor, but also helping him rebuild his physical fitness, Space Marines, Primaris, Gray Knights, Custodes and even... Would he choose to save the world if he hadn't been wiped out by 40k? It all started when he put the grenade in the hand of the Negative Beast... Ps: Warhammer is only used as a background expansion for the protagonist, so you can eat it with confidence even if you have no understanding of it.