Okay, I've read the other worlds you people suggested. And I picked which ones a suitable for this story. So, here's what I added.
Gears of War:
Fairy Tail:
Legend of Korra:
Ghost of Tsushima:
Red vs Blue:
That's all the added worlds. If you have any harem member ideas either from new and old worlds or an OC, let me know at the comments below. Peace Out!