All you guys crying about "no harem plz" this and that are freakin' pathetic. Get over it. If it goes harem, then it goes harem. Either accept it or drop it and move on, too much other stuff to read to worry about this.
In other news, the only problem with a harem here is that it's likely to be a 'fake' harem where while other female characters might develop an interest in the ML, but have zero chance of actually winning over the obvious FL. Either go full poly harem or give the others an actual chance if you're gonna introduce other romantic interests.