The Castle Keep is the seventh stage that you need to go to in order to get the first ending in Castlevania: Symphony of the Night. It is first entered from the left side of the map from the Royal Chapel. The Leap Stone can be obtained from here, which will give you the Double Jump ability that will allow you to enter many other areas of the castle and gain additional items. Its theme music is Heavenly Doorway. In order to reach the top of the keep, where a battle with Richter whose defeat will allow you to get the first (before meeting Maria in the Gallery) and second (after meeting Maria in the Gallery) endings of the game, you will need the Soul of Bat, which can be obtained in the Long Library using your double jump ability. Unfortunately, the Soul of Bat is behind a grate that requires a Form of Mist, so you will need to get that first by using the double jump ability in the Marble Gallery to enter Olrox's Quarters, which will lead to the Colosseum, which is where you can find the Form of Mist. This will allow you to defeat Richter and finish the game, but it is not the true ending. In order to continue the game and get the real ending, you will first need to fight Richter with the Holy Glasses and avoid killing him. In order to get the Holy Glasses, you will first need to obtain the Gold Ring and Silver Ring and wear them in the Room of Clocks in the Marble Gallery. The Gold Ring can be found in the Underground Caverns once you have the Form of Bat. The Silver Ring can be found in the Royal Chapel once you have the Spike Breaker Armor, which can obtained in the Catacombs once you have the Echo of Bat, which can be obtained in Olrox's Quarters once you have the Form of Bat. Defeating Richter without killing him leads to the Reverse Keep of the Reverse Castle.