"Heroes 5". But are they really "Heroes"?

How did Sandro end up on Ashan if, in the fourth game, he was on Axoth? Can he freely travel between worlds, and is he the only one who can? And all he brought to the people of Ashan was his cloak and the name Crag Hack (which Isabel mentions) – is that a logical connection? The developers clearly took shortcuts. And that doesn't reflect well on them in any way.