What if a soldier was guarding a part of the border of the it, when in that world discord was release so instead of when he touched the barrier it rejecting or burn him or whatever he instead falls through the other side as he opens his eyes and sees he not dead and is in fact on the other side of the shield and as he turns around it instead goes back to normal colors it once was instead of it being now red orange color, now returning to blue or (whatever color it was described as) as he now goes into this new world where no human has ever been before nor set foot upon without conversion to a pony.

7843901
Depend on if you want to stay in cannon to Chat's interpretations or not. A human 'can't' come into Equestria without being converted into Equestrian matter, the physics of both worlds are too different for that, without the express intervention of Celestia or Luna of converting a human matter into Equestrian, with the exception of all other life forms which are automatically does the conversions. There is also the issue that the barrier is always moving/spreading and defending it is just pointless because all human tech just disintegrated when converted into Equestrian matter, And Discord in this reality wasn't a physical being as we saw in the show, reeking havorc to the simulation, he was more like a virus in a computer simulation, and was stolen disintegrated and reformed into a war head by the HLF to attempt to kill/decapitate Celestia in the divergent time line, If Discord somehow go free he wouldn't big two shits about making it easier for humans to enter Equestria even for fun and giggles. And there wasn't anything like an army any more in that time, only the Meshs which was more like a enforcer/police force. There is just nothing to protect or fight for on Earth sense the whole world echo system, sense The Last Crop, is essentially dead at that point, no food, and humanity was already on borrowed time before extinction even before the barrier appeared.

I would say the idea would go against the tone or theme of verse and there has been plenty of people writing that idea, so it's nothing really new, but that is just my opinion, and I don't know what you want him to be doing in Equestria which I am guessing you want him to wage a one man war against Equestria, assuming his equipment survive through it. I would say you would be better off creating your own story that has nothing to do with the TCB and just make it a generic porthole that is static that leads to Equestria which he is guarding or something.

7843916
Fair enough. And maybe I’ll do something like that. But still I don’t think so really since many normal equestrians and other species in equestria met a human or a human before conversation