Alternate Realms are worlds that belong to another dimension apart from ours. Entrances to these places are usually generated by ripping the very fabric of time and space, opening a portal between worlds. These doors are generally only temporary, and can only be opened when a certain uncommon event or a large period of time has elapsed in our world, like the passing of a century or the coming of a solar eclipse.
They are usually portrayed as distorted versions of our own world (sometimes even from different points in time), and their influence may even affect our own reality (e.g.: reversions in gravity, sudden changes of weather, or even physical distortions of the environment). The first time one of these realms appeared in the series, was in Haunted Castle. Near the middle part of the first floor of the Banquet Room, a dimensional portal opened before Simon, transporting him to what seemed to be the ruins of a Greek city. Dracula's most powerful minions are usually brought from these places into our world; these conform mythological creatures, spirits and even demons.
The most important of these realms is, without a doubt, the Chaotic Realm. An extremely unstable place deprived of the flow of time and apparently existing somewhere in space. Immense magical powers are accumulated here, and it's from this place where Dracula must gather all his powers every time he returns to the world of the living. Likewise, every time he's defeated, his powers find a way back to this realm. The embodiment of all these powers, known as Chaos, also dwells here. Once the next Dark Lord has started to absorb large amounts of power, Chaos will try to consume the soul of the chosen one with deception and deceit, leading him hopelessly to the path of evil, unless a greater will can keep him controlled.
Alternate Realms, along with Arenas, have become more common environments as the series progressed. They're usually found near the end of the game and tend to be some sort of endurance mode that leads the protagonist to the final confrontation. The most powerful (and sometimes unique) creatures can be usually found in them.
- Haunted Castle - Banquet Room
- Castlevania: Aria of Sorrow - Chaotic Realm
- Castlevania: Dawn of Sorrow - The Abyss
- Castlevania: Curse of Darkness - Infinite Corridor
- Castlevania: Portrait of Ruin - Master's Keep (Whip's Memory battle)
- Castlevania: Judgment - Dimensional Rift, Time Rift
- Castlevania: Lords of Shadow - Dimensional Prison, Shadow Plane, The Underworld