Puzzle Kingdoms happens in the same universe that Puzzle Quest have. It even share some characters from PQ. So I think it must be added to "Warlords Universe" group and maybe even in "Puzzle Quest series" group.
Puzzle Quest is related to the Warlords war games? News to me...
They take place in the same universe, Etheria. The Warlords connection is also hinted at in the title of the first Puzzle Quest.