All castles in Heroes 3.

However, it's hard to disagree that Barbarians develop much faster: Orcs, Ogres, and Cyclops don't need buildings for their creatures, and Hydras only need the Gorgon's building! Also, the creature ignores part of the Hydra's defense and deals significant damage, while the Hydra also attacks creatures, and it's more expensive! The creature can easily defeat an Archangel one-on-one – I've personally verified this!