It didn't appear for me what else do I have to do

>>1 same. I thought at first you had to fight your 3 highest leveled characters. As the 3 you have to fight were mine.

>>4 I just barely unlocked the challenge. I’m not entirely sure, but I think to unlock it, you have to beat the game, complete the three coliseum challenges, and complete the challenge: Trial of the Ancients, which is the challenge which unlocks Monk Maz Koshia. I don’t know how I unlocked Trial of the Ancients, but after I beat that challenge, Hyrule’s Greatest Warrior unlocked for me, so beating that challenge is probably one of the requirements.

>>3 Same here, just beat the game and was looking forward to doing this challenge, but for some reason it hasn’t unlocked for me.

Ive completed the game but this challenge isnt appearing for me. Is there another requirement im missing?

True, I had to go as Maz Koshia instead of Link, but not complaining

Too bad the allies are restricted all the enemys listed are the characters I mostly play.