Camus' Goad Cavalry allows Ursula to take out the Red Cavalry unit
The position also prevents the drag back effect when the Blue Flier attacks her
If they attack her from the left, the wall and mountain blocks the flier from dragging her back
If they attack her from the tile beneath her, Camus blocks off the tile the Flier needs to be on
Cavalry can move up to 3 tiles vs 2 for Fliers, so they can disengage safely
Camus moves to block off the 2 rightmost Fliers, so Berkut can take the one in the centre.
Hit and Run allows the flier to move away from the target after combat
But from where Berkut is positioned, that retreated position can be reached by Berkut next turn.
The tile beneath the Blue Flier is outside the range of the other enemy units.
Berkut, with his special, can take out that Flier.
Enemy units will always attack a unit in their range over chasing units outside their range
So the Red Flier will now target Camus
Camus, with his Special charged, can take out the Blue Flier
The last unit is an infantry, and cannot fly over the mountains
So Ursula can be set up in the middle to take them out as they move along the left pass
Camus is moved next to her to provide the Goad Cav Atk buff
Hope that helps!
