The Doom's Night Explanation-Theory-Connection // TXT theory

TRUE NAMES

As the intro introduces us to the beginning of the story, we see Hueningkai looking down on a looks-like dead bird. Later on, Yeonjun seems to be looking at him from afar as something (like a shadow/person) approaches the younger and says "Silly to care about such an insignificant death... Do you know how many names fade away without ever being called?" which visibly scares and worries him.

I was a bit unsure whether it was Hueningkai at first but the reason I think it's him, is because Yeonjun and Hueningkai are connected in the universe as the 'cursed one' (Yeonjun) and the 'fallen angel' (Hueningkai). If you had noticed, especially in Eternity era, those two appear to be together a lot.

When the shadow disappears, Hueningkai drops the umbrella, scared as Yeonjun runs up to him. He might've or might've not seen the 'shadow', but me, personally, I feel like he did. I'll explain why further on.

As we actually get introduced to the title of the first part of the animation which is called "TRUE NAMES" we see a door open and someone taking a picture of the members sitting and eating on the floor and I am pretty sure it's Beomgyu who took the picture since Beongyu was always with his phone in Eternally.

It's also seen that it's Beomgyu who's taking a picture when they take a selfie.

"We didn't know that there's a world beyond that our eyes can't see." refers to the members traveling through different universes. The one when they're a K-pop group, as was shown them practicing in the room, and the one when they have to fight for each other to stay together as the dragon keeps haunting them.

We get introduced to who the members are in the "other world" or "other reality".