A Monster is the primary unit of combat. Monsters can be utilized by a player to battle other Monsters. To increase a Monster's potential in battle, a player needs to battle with his/her Monster against other Monsters. By successfully defeating opposing Monsters, the player's Monster will receive Experience Points (also known as EXP). After accumulating a certain amount of Experience Points, the Monster's Level will be raised. As the Level of a Monster increases, the Monster's strength and ability in combat is also increased. Typically, Monsters are kept in items known as Monster Boxes, which allow them to be easily sent out into battle or to perform a task. These Monster Boxes come in many different varieties and are easy to transport Monsters due to their relatively small size. All Monsters have one type or two types. These types give them either an additional advantage or a disadvantage over other monsters in combat.
There are different classes of Monsters; these work similar to boxing weight classes, with a lower class being weaker (and consequently at a disadvantage to Monsters of a higher class) and vice versa.
Starter: Starter Monsters are the first monsters you will ever have. Each player begins the game with the choice of one starter. The experience gain of starter Monsters is normal, and they are generally considered around the same power range as emissaries.
Regular: Regular Monsters are the easiest Monsters to catch in the game. With very basic stats and an ultra fast exp gain, these Monsters are great for lower levels, but not so much later on in the game.
Superior: Superior Monsters are also easy to catch. Slightly higher stats than Regular Monsters, Superiors are the next step up with a fast exp gain. They are generally good for Monster battles, but not so much when it comes to player battles.
Emissary: Emissary Monsters are more difficult find and catch. While it will not take too long to find them, it does require some patience. They have good stats and are great for Monster battles. There are a number of emissaries that can also be used in PvP battles to decent effectiveness.
Zenith: Zenith Monsters are hard to find. They come with great stats and great move-sets. There are not too many in the game at this time. They do very well in both Monster battles and player battles. The recommended method to catching a zenith is using a Monster Box designed for its type.
Legendary: Legendary Monsters are extremely hard to find. These monsters are the one of the best, with extremely high stats and damaging moves. They will serve you well in both Monster battles and player battles. It is highly recommended never to run away from Legendary Monsters due to their high rarity. The recommended method for catching a legendary is to use an Ultimate Box.
Ancient: Ancient Monsters are the hardest Monsters to find in the game. These monsters have the highest base stats and power. With base stats ranging from 880 until all the way up to 999, these Monsters are sure to bring down terror to all enemies.