Normally, at most two miniatures can occupy a square. Some miniatures are larger than others. Do the larger miniatures such as the minotaur fill a square by themselves, or can they share the square with another miniature?
In the rulesbook on page 15 (Full or blocked spaces) it's said:
Each Space can contain a maximum of two Characters at a time. A Space with up to one character in it is still considered to be free, since other characters, enemy or allied, can still enter it and shoot through it normally.
There's no mention of monster size here. Moreover in the same chapter, the example pictures a space with a lone troll (which is a big miniature) in it as free.
The huge monster rule was introduced in Beyond the Grave. some monsters take up a whole space, and when they move they shove other characters out of the space.
there were no huge monsters in the core game (despite their miniature being big)
monsters considered huge are:
- Dread King (beyond the grave)
- Ignos (Wholed Lot of Lava Expansion)
- Dragons (various dragon expansion boxes)
- Any mounted hero or enemy (Riders)
and I'm not 100% on these guys, but they look like they should be considered Huge:
- The Underlord (Inferno)
- Malkhor (Riders)