Which monster do you like the most in Heroes 5 at level 5?

Hydras don't even need speed or initiative; you can not move them at all and they won't attack anyone. The point is that 125 hit points multiplied by the regeneration rate make the hydra a durable unit on the battlefield (and you don't feel as bad about losing them). And the main offensive force in the Dark Elf castle isn't assassins or even Dark Knights, but the hero – a Warlock with 30 spell power, upgraded Chaos magic, Enchantment, and a Lucky Wizard. And hydras are essential for allowing the hero to use their spellbook even more times.
Conclusion: The strongest monster of level 5 is the Lich, but the most useful one for its faction is the Hydra.