Exactly 1000 - no, it's not possible. Only if it's a player, and they are in no more than 3 stacks, all gathered in one place. This is practically impossible, so there's no point in considering such a situation.
The AI will divide archangels into 7 stacks when fighting against a single demon.

7 stacks might not even reach their destination if they are expertly slowed down. But, of course, then the archangels must be "leaderless," that is, without a hero - the hero can solve the problem in two moves, either with a dispel, healing, or even speed; and they shouldn't move first, which is possible not only in the case

1. It must be in the Castle, and it must be with the Tactics skill. So that the turrets shoot first. In all other cases, the archangels move first.

,
but also in the case when we attack a Castle without a Citadel, while having ballistics.

In general, I don't like these kinds of challenges. Small maps often have all sorts of twisted tasks, and I prefer to build up my defenses, develop my hero, and then move into enemy territory.:smile13: