The enemies are split into 2 lanes. The left side has 3 Samurai bandits and a Mindflayer. The right side 3 Rangers, 2 Energist, and a Mindflayer. All bandits are dark element and have -10% light and slash resistance.
If you are having difficulty with this quest, you can try bringing 2 tanks, 1 from your own, and the other can be the Warrior of Light npc friend unit. Recommended to get some slash resist against enemies on the left, and magic + missile resist against the right side. Calculators have a pretty good advantage here since their abilities have good area and long range, being able to reach the other side for heals or damage. Snipers/Gunners like maybe Frederika can help snipe the Mindflayer before they start spamming their area paralyze attacks on your team.
Sakura's pretty good here since she has strong area attacks, and a Light damage dealer with a good defensive area buff.
Ildyra as the calculator for extra heals or area damage.