considering that the vast majority of my characters are mages I'd imagine they'd probably get along decently
my Morrowind, Oblivion and Skyrim mages would all be swapping notes and discussing the various conditions their part of the timeline was in
The Morrowind mage would brag about being able to cash levitate and lock
the Oblivion mage would probably brag about, arguably, being the most powerful of them (considering how overpowered mages are in OB)
the Skyrim mage would probably whine about how, arguably, he's the weakest of them (considering how underpowered mages are in SR)
my Fable Mage and Dragon-Age Mage would probably also be in that group somewhere
my Two Worlds mage would be cracking stupid jokes and groaning really loudly everytime he stubbed his toe
my Borderlands Hunter would probably be teasing my Fable II and III characters for using such primitive guns
and then my Borderlands 2 Commando would probably tease the hunter for using such a primitive gun
My Crackdown 1 and 2 characters would probably tease the Commando for using such primitive guns, and pity the Fable II and III characters
my Saint's Row character would pimp slap all of these guys, hang the Fable II and III guns on display as his "historical [censored]", re-purpose the hunter's gun as some kind drug tool and would actually use the Commando and Crackdown guys' guns
and my minecraft character would be pulling up the floorboards and digging underground
that's all the ones that come to mind right now