Level, or the action of Leveling Up, is a statistic found in most metroidvania-style Castlevania games. It is a measurement of the character's battle experience and relative ability. Levels are generally obtained via gaining Experience points, which are in turn obtained through killing monsters. Leveling up makes its effects come into play immediately, including an increase in the character's vital statistics like Strength, Constitution, Luck, Intelligence, Hit Points and Mind Points.
The idea of leveling-up a character originally began in Castlevania: Symphony of the Night as one of the many RPG elements added to change the style of the game from the more traditional adventure platformer games in the series. Each enemy is usually worth a certain number of experience points (although in some games, like Harmony of Dissonance, the point value varies depending on the relation between the player's level and the enemy's), with the player requiring a certain number of collected points to advance to the next level. Every level slightly raises the various stats of the player, making them that much stronger, better at magic, luckier, etc. Usually, the "Level-Up!" phrase appears above the head of the player to signify a successful level-up, followed by a brief pause in combat.
The main playable characters are not the only ones capable of raising their level. Various Familiars and Innocent Devils also earn experience points and thus, also level up and become more powerful as this statistic increases.
All of the RPG-styled games after Symphony of the Night use this method to advance players so that they can become stronger while progressing through the game, allowing the game to become more challenging as they advance. However, many players tend to find areas where they can gain many levels quickly by beating enemies. This skill, called "level grinding", combined with the practice in these games to add weapons to boost the player's strength, tend to give the games the appearance of being much easier than they are, especially when compared to the previous platform games that do not include an RPG leveling mechanic.
Note that few Castlevania games with this feature of leveling-up also come with the bonus of instantly replenishing the character's HP upon gaining a level (like in Symphony of the Night where Alucard's health is refreshed on level-up) which is beneficial in the middle of a battle. Games like Aria and Dawn of Sorrow are more challenging in this term, as Soma Cruz's health is not refilled on level-up.
Game specific information
While also determining the strength of Alucard, his level also modifies how much experience he receives from defeating enemies. If both their levels are equal, then he gets the same amount of points listed in the monster's bestiary. Otherwise, if the monster's level is higher than Alucard's, the experience is multiplied by 1.25^(Level Difference). If it's lower than his, then it is multiplied by .66^(Level Difference).
The Experience needed to level up is calculated as 25*Level^2+Level*25-50.
In this game, there are 3 variants of the Hard Mode, which caps the player's level to Levels 1, 25, or 50.
When unlocked, the Hard Mode of this game caps the maximum level to 50. Establishing a Wi-Fi Direct Connection between Order of Ecclesia and Judgment increases the Level Cap of this game to Level 255. Alternatively, beating Hard Mode capped on Level 1 will also increase the level cap to 255 for the Normal and (Hard capped Level 255) Modes of both Shanoa and Albus, as well as the New Game Plus.