my friends call me obstructa and i didnt even know what it was until i found out cats of the cosmos was the one after into the future in the battle cats
Theory: This is a special boss mode with 10hbm, where when you do a PR, with a 10 Hour Burst as your misc, and you use it, it activates. Further support of this is in the description: "I cannot be replaced" which most likely indicates another 10 Hour Burst Man, that one being you.
I wonder if this is a theme for the 10HRBM or for the apocalypse bird. The description talks about someone claiming that the forest is their home saying that "they cannot be replaced *ever* *again* " This means that either 10HRBM was replaced once (perhaps by the birds) but it can also mean that the birds were replaced by the 10HRBM. I find the latter more possble considering how the 10HRBM possesses twilight which is obtained after apocalypse bird is defeated (in L corp). We can also hear the motif(?) from "Too Many Trumpets" in the background during this part (1:35). More reasons why I think the latter is more possible is because the birds originated from the forest. Although we don't know the orgins of the 10HRBM, we can see him outside of the forest on multiple occasions making the forest more of like a place for him to dwell when he wants to instead of a home.