This is something I've always kinda' had trouble wrapping my head around what exactly prompted the end of The Great War and the subsequent signing of the Pax Cybertronia, and the following Great Upgrade ('Bots and 'Cons to Maxies and Preds). IF we are to consider the admittedly HORRIBLE cannon of the G1 continuity (which leads to the Beast Wars), we are led to believe, with a little re-working, that sometime after Prime sacrificed himself to restore Vector Sigma (after reviving to slap his bitch Rodimus around and fix that whole Hate Plague mess), Star Saber and Deathsaurus (y'know...the name that MAKES SENSE?) had their little spat in Transformers Victory, I would hazard the guess that it's the Transformers Zone OVA/manga/story/whatever that marks the end of G1. It's simply a reasoning of an "End-all, Be-all" of battles only fit to end the saga of Generation 1 (assuming one wants to ignore G2....OW CONTINUITY BURNS). I mean, good lord, huge horrible Unicron-esque "Dark Nova" thingy revives Galvatron and makes Super Megatron? Star Saber finds the lifeforce of the universe and uses it to revive Optimus, making him Star Convoy? THE FINAL VILLAIN'S NAME IS "STAR GIANT"? Randomly awesome fun, and it works for me! Thoughts on how the Great War ended?