Um, those two rules you quoted actually conflict one another on the very point Myou mentioned. I would argue that the Very Small Creature one is the "more specific" one (and therefore takes precedence) on the theory that most combat rules are written for the generic [medium] case and therefore that any rule specifically mentioning a size category is meant as an exception.Ending Your Movement
You can’t end your movement in the same square as another creature unless it is helpless.
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Very Small Creature
A Fine, Diminutive, or Tiny creature can move into or through an occupied square. The creature provokes attacks of opportunity when doing so.