As far as any scholars have recorded the human race is by far the most abundant race in the whole of Valeria. This could be down to their impressive ability to adapt, humans are able to live in almost any area. There are only a few terrains that humans find inhabitable, mainly deserts and barren wastelands.
Humans often move into an area and change it to fit their needs, as opposed to respecting the natural landscape. Once the area has lost its use and value to the human race, the humans then move to another area and repeat the same process. Their ability to adapt seems, to many of the other races, to be more of an ability to adapt their landscape/environment rather than adapting themselves to their environment. Due to this the nature based elven race has always had uneasy relationships with the human race.
Humans, themselves, have varying ethics. Where some humans will value community and equality, others will value wealth and personal prosperity. This has caused, and most likely will cause again, arguments that have escalated into full blown wars that have lasted years. These wars can even drag in other races for various different reasons.
Thankfully there hasn't been a major war for just over a hundred years, where the whole world of Valeria was thrown into a massive human civil war which involved many other races to help stop. In many ways it was a war that was fought on more than two fronts.
Humans have utilised the peaceful times to rebuild damaged cities, repair relationships with other races, form various new organisations, and learn many new trades. Thus allowing the human race to prosper in many different locations all over Valeria.