Some theories I made up after watching the HOLOEXPO2026 HOLOSTARS anime short. I'm rambling, my lore brain is going BRRRRRRR, so please don't take my words seriously nor take this as canon.

Bro, imagine we get another scenario of the JP senpais getting stranded in Elysium having no idea how to get home, with Astel's and Aruran's powers not working in Elysium (Aruran can dimension hop, check his Re:Birthday stream; Astel have his lore videos in his own channel). Like sure, some of the JP senpais can fight, but what if they are nerfed in Elysium, due to the number of Corrupted Beasts.

Basically, the Corrupted Beasts are one of the main blockades.

The more Corrupted Beasts there are, the harder it is for the JP senpais to travel or even live in Elysium. Maybe just living in Elysium for a long time might spell disaster for the JP senpais. Remembering that there was a theory that Miyabi may have something to do with the world tree in Elysium, and how the HoloExpo 2026 anime short implied that Elysium is in a video game based on the past, this may have something to do with a paradox of EN and JP meeting together properly. This is probably why JP and EN have difficulties meeting up, and why Tempus and Armis usually have missions that have them hunting down Corrupted Beasts.

Since watching the HOLOSTARS EN shorts, I had this idea that the EN kohais can freely visit the HOLOSTARS house the JP senpais reside in, and I thought back then that the JP senpais could do the same. The HoloExpo 2026 short showed me that, yes, there is a possibility that the EN kohais can hop in-between dimensions freely, but not the JP senpais. As the short shows, while they can travel to Elysium, there is a huge risk that the they cannot travel back to their home dimension, due to Elysium's nature.

Now that I think about it as I re-read whatever the hell I just typed, it's kinda like an analogy how the EN talents can visit Japan anytime they like.