This is what my hero looks like.

The funniest thing is that even if you're given a character with a portal and invisibility right away on the island, it's not really possible to complete it that quickly: to use the portal to a city, you need to touch the fountains. And the fountains aren't in every city; for example, in the Sylvan faction, you constantly need a walker or a beacon (but you can't get the beacon right away). What to do: level 1 = 1 day, + travel to the portal to the water elementals.
By the way, it's quite difficult to complete many locations using invisibility (especially if you're a master of air): portals, the tomb with the golems, and the quest locations for the Sylvan faction. Of course, it's possible, but it's far from very easy; you'll spend 10-20 real-time days on Save/Load.

by the way, in Might and Magic 8, there isn't really a plot at all

There is a plot there, and it's quite global, but there are few missions – which means this plot is poorly revealed; the scriptwriters from 3DO were fired (around the middle of the development of the 7th part).

In general, in this game, story missions are completed last.