Reversal Rivalry - Valorous Rhapsody Challenge #3
This was how I cleared the third challenge on my main account. It's a shame this run was not clean and took 15 turns. I did it earlier with my alt and had a much better run then but wasn't recording. Used the same characters though. I did have all the stat buffs for the event which you can get for farming the event.
General strategy is position your characters like Leon and SPElwin next to enemies and use Chivalry to reveal them from invisibility, then attack them on the same turn. Lana used Scepter of Divinity to attack from range. When enemy Licorice does her ultimate, counter it with your own Licorice ultimate so the tiles stay friendly to your team. If you allow the tiles to stay for the enemy, it allows them to run faster to the goal. If you continually reveal the enemies and stay near them, they will attack you, instead of running for the goal.