Final campaign - "Too Bright for Darkness [Campaign 7 - Mission 2]"

I don't know about this one, but the first mission is perfect for a Knight. Considering all the strengths of the Confessor, I think they'll complete the mission just as well as a Priest (I also played through it as a Necromancer). You just need to avoid rushing forward like I did, and instead wait before completing each "level." Overall, the mission isn't difficult and allows you to feel your superiority and the superiority of the "divide and conquer" method.

As for the Tears of Ashi, it's not on this map. You can simply collect the second Shanti-Iru artifact for your collection.