Why is this a separate entry? So that someone like me would come along and write a review of it, of course. We see Oragon enter a run-down modern Japanese apartment, do some product placement for the game he's from, and celebrate his birthday alone as all of his friends can't make it. It's unclear if this is Oragon as he exists in the timeline of the Monster Strike Anime starring Ren and all them, or if this is just Oragon the mascot character a general representation of Monster Strike as a franchise, and it doesn't seem to matter. Point is he's living a sad lifeand appears utterly alone, so if it is in that Ren timeline I guess the power of friendship and all that was a lie. Anyway he's quickly isekai'd to some sort of library and we get the setup that this episode is just a framing device for the new Monster Strike Anime that is going to star characters like Lucifer and primarily take place in the Monster Strike world rather than our real world. Maybe in that sense it can be seen as a prequel to the other show where eventually all the worlds are blended into ours as more and more portals open up, but that doesn't explain Oragon's presence and really I get the sense that these aren't the sorts of questions they were expecting people to ask or have to come up with answers for. This episode only really matters to explain the little stingers in between arcs later where the mysterious box character is introducing stuff. If you skipped it you'd still probably be fine because that stuff doesn't really matter to the main plot and isn't brought up again until the final arc where it turns out it didn't really matter much anyway, except to presumably sell more Oragon and Pink Oragon plushies. So it's an episode designed to setup merchandising opportunities in a franchise that already only exists as a merchandising tool for what was already the most profitable mobile game ever. It exists because money, and you probably don't need to watch it. 6/10