That depends... Are you dying because you lack healing? Or maybe because you lack damage? Anyway kick out Indra and take Nike instead. Then I would say go with Cassiopeia plus def debuff from Gawain as extra skill.
Or you can also kick out Perun and take Amon Unleashed instead of her. Then I would take also Cass but with Asmund double/tripple atk rate debuff. (Just to be safe)
Anyway I feel obligated to post video of this event, this time I can't kill it in one turn so I went with auto battle win. Funny thing out of three times that I tried to do it this is closest I came to losing.