The only evolution system

In this world,there are no demons or monsters.It is actually quite peaceful.Human society at the same level of technology as it is in your world,reader!The only difference is that theres no war between humans anymore.After all the whole conquering annoyed some scientists and they just created a virus that unalived all those who wanted to kill eachother.So now wars gone or what?The answer is…not really.As soon as these guys stopped cruelly murdering eachothers,a new thread must have been found.And so they just found an other species to conquer.May you call them spirits or like whatever you want to.Those ‚spirits' were a peaceful race that kept themselves hidden.Not wanting to get involved in any conflict.But as soon as they were discovered,the bombs started falling again.And just like that there suddenly was a full on world war going on.The ‚Spirits' of course,not prepared for that turn of events,gotten evaporated until just a few remaind.Those few fled into a mirror dimension called ‚The border'.A paradise unreachebal for human kind.But there would not be a plot if not for plans of revenge against humanity from side of the spirits and the never ending search for war in humans.And just that you know,I am one of those surviving ‚spirits' like your kind prefers to call us.Now we just need to find a weapon.