What skills should I upgrade for Friede in the final mission of The Grand Escape?

In this mission, everything depends on leveling up the heroes. Characters like Wolfsten, Kujin, and Zephyr are well-developed; they have a lot of artifacts, the gnome has light magic, all the runes, Kujin has anti-darkness, shouts plus leadership, and Zephyr is level 30 and the main magic summoner. But what should I level up for Friede? She's a Knight, level 20! She loses in the final battle, even on auto-battle! Instead of her, I used Duncan in the third mission. What does she need to level up to defeat the Demon?