English books of a French Canadian

Can someone help Sam? Did he simply dream it all?

There was a series of novels I read at summer camp after fifth grade. The setting was a group of friends sitting around and playing a D&D-type game, but with a hexagonal gameboard. But very quickly it cuts to the world of the game and follows the characters as they go to war. Not sure whether they were in the dwarf-elf-human-etc character-class system of pseudo-D&D, but I imagine they were. Kind of, also, like Dragonlance? Anyway, their fates are determined by the humans who are "playing" them.

And then the twist is, it turns out some higher-level world is "playing" the humans! Which is worthy of William Sleator?

Anyway, I've asked some people, but none of them could help me. Maybe because I borrowed the books from a French Canadian? But they were in English!

Any idea???