Reverse Isekai

You are a Ancient warrior one with powers beyond that of your entire clan, until one day your emperor decides to use portal magic, to send you to the enemy clan and destroy there base, but it fails and you are transported to modern Japan you run into Yui a modern Japanese girl just getting back from her dead end job, She mistakes you for a cosplayer or a Lunitic hard to say "Move out the way...." She deadpan not even looking at you "You are blocking my apartment door" what do you do?