Here's a boy, no older than nineteen, quietly sipping from a mug in an interdimensional bar. There is a rather large rather ponty-eared panther lying next to him, purring softly as the boy scratches its head. Floating in front of his face is a book, which he is absently reading. Given that he didn't walk in from the door, it can be presumed he is probably a tenant who came here from one of the rooms upstairs at some point.
Fernando glances at the supernovas when past-Fernando is surprised. He doesn't move otherwise.
They discuss how to combine magic systems and solve each other's problems. Felix is his usual supersped, extremely loving and caring self, and Kaede is Kaede. The triplets and Katur's attraction to her becomes increasingly obvious, but the opposite is not true until she mentions she wants to flirt with them.
"It occurs to me you might object to my watching what follows. I wouldn't want to intrude in your privacy."
"No, but the fact that they go to different worlds will limit how far I can follow them. I can show what happened to any of them while the portals were open, if one of you holds the door, but once they close I will no longer have access to those worlds."
...and here's a boy falling in magical love with five people as he walks into the interdimensional bar.
"—yes, modulo circumstances. They will be annoyed with me for everything they've been through. I will have some explaining to do."
"It's... complicated to explain without explaining more about how my magic works. If it helps, I could see the future at the time I did it, and I knew it was going to be averted."
"I told this to your brother before he opened the door for the two of you. I died, a long time ago, and made myself reborn twice. I'm the half with the memories and the old powers and limitations. There is another me in my world—they are also named Sadde—and they remember nothing, but they are not limited by my sacrifices, and they can use the tools I made, so they can become much more powerful than I ever could. One of these tools is what threatens to cause apocalyptic damage, but it will be averted and the tool mastered and used for good."