Responses
I'm guessing that the parasites that each of the warriors fused with to use their gear combined with their dying regrets and each other to form a kind of legion parasite. This is similar to how the antagonist absorbed each of its prey to become stronger.
oh yeaaahh i totally forgot about that ヾ(☆▽☆)
Wait what? Am i reading it right or is it all those parasites turned into one or is it their souls