> Conflict is part of life
What human being call war is a constant state for most animals. Eat and be eaten.
> and human nature, while usually relatively peaceful
Humans are relatively peaceful because we are
(a) a very social animal and
(b) not natural predators, i.e. we are poorly equipped to handle meat eating. Without cooking we basically cant, we lack the necessary teeth etc, and we dont even like the sight and smell of raw unprocessed meat, while for example a lion loves it.
> will sometimes end up in conflict because another evil person wants to archieve world domination or whatever.
While most people are more or less goodhearted, there are always some evil people around.