Scenario: Can monster be targeted?
TL;DR No

For reference, "Line of Sight" (pg 12) from the Rules of Play:


  In order for a figure to have line of sight to a space, a player must be able
  to trace an uninterrupted, straight line from any corner of that figure’s
  space to any corner of the target space.
  
  If the line passes through the edge of a map tile, a door, or a blocked space
  (a space containing a figure or obstacle), the target space is not in line of
  sight (see “Line of Sight Example” on page 12).
  
  If the line passes along the edge of a blocked space (see “Line of Sight
  Example” on page 12), the target space is not in line of sight. However,
  if the line only touches the corner of a blocked space (without passing
  through the space itself ), the target space is in line of sight.


Now let's address the possible lines from the Hero's space:


Top left corner


Any line from this corner must pass through the Hero's space. The Hero is a figure, so the Hero's space is a blocked space. So all lines are invalid because they pass through a blocked space.


Bottom left corner
Bottom right corner


For both of these corners, any line must pass through or along the Obstacle space. An obstacle space is a blocked space, therefore all lines are invalid.


Top right corner


Only a single line can pass from this corner through the obstacles. By geometry, that fixed line does continue to the Monster's bottom right corner, but passes through the Monster's space. A monster is a figure, so therefore the Monster's space is a blocked space. Therefore, the line passes through the edge of a blocked space and is invalid.

Summary: All possible lines are invalid; the Monster can't be targeted by the Hero.