The final battle took place on the opponent's snowy territory on turn 141. I failed to rush the opponent due to a lack of movement points; Iona was attacking. Kirill had better stats and an army, but only 15 mana.
However, this was enough,
combined with expert haste, Iona had 120 mana, but no powerful offensive magic – she couldn't counter it with anything other than oil.
Thank you for the game!