I killed the first 2 opponents, moved Margus as close to the door as I could, and moved Ansom such that he would be able to attack the first archer on the right on his 3rd turn. I also moved Cotton right in front of the door on the 2nd turn.
on 3rd turn, began killing the two archers on the right (it takes 4 turns total). I also used Cotton to damage the knight on the far right of the castle door.
as the turns go on, while Ansom is doing his thing, I move Margus to the far right, right in front of the door, Marie right behind him (to support both him and Ansom with her 6-range Heal), and I began to move Cotton to the right side entrance.
all during this time, Alhambra and Serdic are chilling in the back waiting for the horsies to come.
once Ansom kills the 2nd archer, that's when the door will open and reinforcements will show up.
Alhambra and Serdic together can kill 2 of the horsies and move out of the way so the other 2 horsies wont be able to attack them. on the next turn, they should be in range to kill the remaining two. EASY!!
move Margus up 5 spaces and he should kill the soldier that Cotton hurt. This will also put him in position such that the 3 baby soldiers will come at him instead of Rukia. Move Ansom right in front of Marie and have him attack the soldier in range.
now this is the key point!!! Remember Cotton? She is going for the kill on the soldier chilling by the side entrance. Move her right within his movement range. f the soldier stays still, he can be killed in one hit with the Fire Dragon attack. If he moves back towards Rukia, you misplaced Cotton and need to restart.
if all goes well, Rukia can now be saved.
On the enemies' turn, Margus is going to get hit HARD! once that is over, use Ansom to attack the enemy he attacked the previous turn, that enemy's position should be right behind Margus. If so, proceed to move Margus back 5 spaces, he will kill the solder in his path and he will also be out of range from the other two soldiers. Use Marie and heal him.
Continue zoning your enemy. When he's free, move Serdic towards the right side entrance to meet up with Rukia, you shouldnt need him for the castle battle.
of the 3 threats Rukia was facing, she should have 2 of them on her tail thanks to Margus' distraction (one of them will remain fully focused on Margus). Rukia and those soldiers both have 6 MOV so they will never overtake her. Once Serdic reaches her, he should be able to handle them... but to be sure bring Alhambra too!
When all is clear, move Ansom up to the balcony-ish area and snipe the boss to death