Valid reason to start/stop a war

Hello all,I’m currently doing some world building for a novel.I have 4 main races in my world,humans,dwarves,elves and beast men.I’m trying to figure out a valid reason to start/stop a war between them I was wondering if I could get some suggestions. I have 5 kingdoms (2 human kingdoms and one for every other race) The points I have already are: -The assassination of the first daughter of the human kingdom (A) blamed on the dwarf kingdom,although carried out by human kingdom B.

-The colonization of parts of the elf kingdom by human kingdom B

-The alliance between the elves and the dwarves

As for the reasons for the war to stop,I can’t think of a valid (and not cliche) reason and would be grateful for any suggestions.

Thanks in advance!