My apologies for the necromancy, but have some Content!
It had taken him a long LONG time, but Negi was finally finished. After years of work and decades of planning, he had figured out how to solve the primary problem in his timeline. Everything in his loop eventually came back to the fact that the dimensional magic sustaining Mundus Magicus was going to fail, and soon.
Asuna doesn't know where she came from? She's the Twilight Imperial Princess, a nigh immortal magical entity that forms the basis of the spell. Chao Lingshen making trouble and threatening the Status Quo? She's trying to prevent the genocide of everyone on Mundus Magicus by revealing magic so that the mundane world can work to help
save everyone. Even Evangeline A K McDowell, ancient vampire and High Daylight Walker was the result of the meddling of the Life-Maker, the mage responsible for Mundus Magicus.
He'd tried for loops to find another way, but in the end the keystone of the magic that bound Mundus Magicus could only be repaired by Asuna sacrificing herself as an alternative base and being locked in magical stasis for a hundred years.
In his first timeline he'd spent years working to terraform mars so that Asuna's sacrifice wasn't in vain. He'd realized later on in the loops that there had been some time travel shenanigans then. Once the loops had started and as the unification of his timeline had hit him and other timelines of memory had folded into his own.
But now, Finally, FINALLY, he'd managed to figure out a way to terraform Mars in the limited time he had before the dimensions collapsed. Sympathetic magic cast mixed with nano-tech was a wonderful thing. He'd even used the years of accumulated blackmail and politicking experience he had gained beating bureaucracies into submission in his original timeline to set things up so that the nations of the world would work together and begin to head for the stars again.
Now that the looming threat of planetary genocide was out of the way Negi could put his all into testing and developing his pet project.
Dimensional Travel! Eva had managed to master it well enough that she'd gone timeline hopping back before the Time Loop, and after years of being trapped, being forced to deal with repetition over and over again, he was glad to finally have another option. He was even more glad that this option would give him a bit of privacy. Not that his class wasn't precious to him, but the constant madhouse lifestyle was a bit wearing.
Finally, a chance for some alone time! Peace and quiet! With that in mind Negi triggered the magic and the world went white. When resolution returned he found himself on an old fashioned steam-train that hummed with magic. He wasn't alone though, there were a number of other people in the train compartment with him. One of them, a very fit looking asian boy with his black hair in a braid down his back had a long-suffering look on his face and said "Hi, I'm Saotome Ranma, Sorry, 'bout this".
Break
AN:
So yeah, this is my vision of how Negi may have entered the fused loops. Misfired dimensional magic. I didn't think that had been shown before so here ya go. Also, whether or not the magic would actually work in the future if he spent more time on it is up for debate, he did basically take his first out here after he'd finally resolved his big long term problem. He just wanted a week or two of alone time. Sadly, that didn't work out