Difficult, but doable

my team and stats as follows:

Olivia, lvl 20 4* with hone atk 2

Xander, lvl 40 5*, inherited fury 3, quick riposte 2, ignis, and has speed seal to prevent a double attack from the mage

Anna, lvl 40 5*, inherited fury 3 and threaten def 3

Cherche, lvl 37 4*, nothing special.

Use cherche to bait the healer with the other 3 in a right angle formation just under the left choke point (Olivia in center). Pull cherche down 2 spaces, and use your honed Anna to ORKO Camus. Dance Anna below Olivia, and put xander where Anna was. Olivia should survive a round from the healer. Attack with Xander, and move the others to safety. Take out the healer in the next turn, and then carefully kill off the axe users while dancing if necessary. In the last turn, you should have a Xander at 1 HP, and with Olivia's dance, you should be able to kill the mage and get your 4* Camus. This is not easy, but it is very doable.

Olivia

Xander

Anna

Cherche