Requiring defeating 15 Formidable foes was ridiculous. I thought the point of doing a challenge was to work "with" your partners instead of against them. I saw too many instances of someone taking a foe that was one of their weaknesses (based on profession) just because it was a "formidable." I lost out on too many opportunities and turned this into yet another grind. This was just as bad as the Highest Chamber task.
@Kiyone57 When we get the formidable foe requirement, it's best to play fortress challenges on your own (except for the highest chamber requirement.) Most of the time, I only get one formidable foe from each challenge.
In the last minutes I got my last formidable and alohomora. Unfortunately I wasn't in time to get my rewards.
Now the empty spot is glaring at me..