Ending on turn on space of another character

[Crexis]

Can large creature (10x10) move onto a 5x5 space where an ally currently is and then stop and attack an enemy?

And basically end his turn on top of another ally or npc?

[GM Rednal]

No. Creatures need to be at least three sizes different to share a space at the end of a turn.

[PokeyCA]

No. You can generally not occupy the same space as another creature. (see Movement, Position, and Distance / Moving Through a Square in the Combat section of the Core Rulebook). Exceptions are when the other creature is helpless; Fine, Diminutive, or Tiny; three sizes larger or smaller; plus any other creature specific exceptions (can't go through the space of a gelatinous cube, etc.)