New era.

Congratulations!
Many people complained about the Canada map, so I tweaked it several times. Yes, Udo removes buffs.
Against Sigrif, Chaos is useless; Darkness is definitely preferable. I would replace Education and Luck with Attack and Leadership.

I beat Sigrif on the same day and finished the final today. In the end, I didn't give up on Chaos; I just replaced Education and invested in Darkness. Overall, I used Subjugation and Vampirism a few times. Otherwise, I beat him with Chaos. I got the Boots of the Earth, so Meteor Shower dealt 2-2.5k damage, and with Luck, it dealt 5k. He had protection against everything except Earth; his overall defense only reduced Chaos magic damage. I beat him on the first try, losing Minotaurs and Witches (I got unlucky, and a Berserk cast a spell on the Witches, and then they cast it on the Minotaur, and they killed each other, haha) and Beasts, but it was just by chance. Overall, I thought it would be tough, but it turned out to be quite easy.
To beat him, he needs to increase the army's growth rate a bit. Because I had more Dragons than he had Devils. He had more of all the other units, but fewer Lords than I had Witches. That's why I quickly captured Dwell with Witches and Dragons.

Regarding the final: I initially tried playing as Askh, and I easily defeated Necropolis, but Udo is invincible for Askh. I also made a mistake and only later realized that I could assemble an army of 6-7 units. Unfortunately, there were no racial Dragons there, which also affected the battle. I was critically short on resources for the Mentor; Darkness didn't drop until the very end, so I started with a not-so-great build. But I think Udo can't be beaten by Askh, at least not with the native Elven troops.
I tried playing as Udo and easily killed both of them without any losses. Chaos is just too overpowered. And the Imps drain all the mana in two turns (and I killed everyone in three turns). Udo is officially overpowered. Maybe I'll try playing as Askh again sometime; I won't play as Necropolis, I don't like Undead. And he's objectively the weakest there, although you managed to beat him, I saw your screenshot, but I don't feel like trying to beat him.
Thank you for the trilogy! You have the best maps! Although Elemental Equilibrium is also a great map; if it had a difficulty level like yours, I think it could compete as a single-player scenario