Posts from How do you kill a summoned phoenix? Auto-translated

That's all well and good in the game, but what if someone summons it in a duel on the UMC?

Hmm, personally, I try not to pay too much attention to the Fend and immediately counter the enemy troops.

That's all well and good in a game, but what about in a duel on the anniversary, if someone summons it, then how?

In a duel, Fen is summoned with: Dyraell, Jaleeb. And against these heroes, Haven doesn't work. Against Dyraell, they usually take Ravenna – she deals with Fen using cold, but it should be noted that Dyraell doesn't summon Fen in 75% of cases because he doesn't have enough mana.
Fen from Jaleeb is much more serious and dangerous. Against Jaleeb, I usually play Iris (and everyone knows what she has), so there are no problems with Fen there either.

I once played as the Demons, and there was a Chaos magic ability that gave a bonus to ice spells (killing at least one creature) – this was in the original Heroes of Might and Magic V. I took it then and didn't regret it – I even got to use it.

For Inferno and Necropolis, it's very simple: for the former, we'll use Cave Lords – they can kill him with just one attack; for the latter, we'll use Death Harbingers – they use their ability and also kill him. A simple tactic.

There are many ways to control a phoenix. But since we're talking about Humans, who don't really play the Chaos or Summoning schools, you can either use Darkness spells or brute force, or eliminate the enemy army so that it disappears.