Elves are quite well-balanced: they have both "tough" creatures like Ents and balanced ones like Unicorns. But the elves' strength lies in fast-paced gameplay; they are very proactive. They are strong in the mid-game, but with prolonged development, they lose to Necromancers, Humans, and Mages. Elves are characterized by low survivability and relatively low damage, and defense doesn't always save them.
Don't elves have low damage?
The hero's attack grows a bit slower, but the creatures have good damage.
It's worth noting that the longer the game lasts, the more troops are encountered in battles, which means the Avenger skill has a greater impact.