-Tonics: Robin (HP, Def), Morgan (HP, Def).
-If the Swordmaster has both Pavise+ and Aegis+, attack him with Morgan first. Then Robin can slingshot off of him. If he dies, then Robin can use either the Berserker or the Sage instead; the important thing is clearing the path for movement.
-Equip Chrom with Beast Killer, then have Robin attack Aversa with Celica’s.