Not sure, whether this was already mentioned. However this can make the game unbeatable.
1 Pick cornac corruptor
2 Unlock Shadowflame
3 Invest into Wraithform
4 Find some dungeon near rocks.
5 Enter dungeon, cast wraithform , leave dungeon.
6 Step into rock on globalmap.
7 Wait till wraithform runs out.
Not sure about current version, but earlier repeating steps 5 to 7 would eventually bring you to the zone right under the main continent without any ambushes/dungeons/towns generated so you never get back.
UPD: Tested it in current version. Still works as described.
EDIT: I've erroneously typed "shadowflame" instead of "wraithform" in steps 5 and 7. Fixed.