Demon

Demons are random event mobs that spawn near a player as a form of combat challenge.

Existence
A certain amount of demons constantly exist, and they are not gone when they are killed. This means that one can see the same demon spawn again, despite being killed earlier. They can be banished, however, using a Fairy Blade. Only the final blow must be struck using the blade, but it will break the weapon. A banished demon will drop its skull, which will be labeled with the player as the slayer of the demon.

Spawning
A demon will have a chance to spawn near a player about ten times an hour, but they only spawn when the player is above ground and in an area with low block light. They can spawn in the day, but not in a lit area. They will spawn within 30 to 55 blocks away, so they can be avoided. Demons also have an increased spawn rate in the Nether.

Nemesis
A player can gain a certain demon as a nemesis if they have killed it the most out of any player. When a player has a nemesis (or multiple), the demon that spawns during a random event that targets that player has a strong chance of being that demon. This recognized by a spawning quote from the demon stating that it has returned specifically for the player. In a nemesis event, the demon spawns within a closer range of 20 to 35 blocks, making avoidance of it harder. Nemeses can be lost, however, by the demon killing the player it hates multiple times. Every two kills the demon makes erase one kill the player has against the demon.

Tiers and Leveling
There are two tiers of a demons: the default tier, simply called "Demon," and the "Archdemon" tier. Demons start at level 1 and level up as they are victorious or unslain before withdrawing. A demon's level determines its health, attack damage, and likelihood of using a special attack. Once a demon reaches level 7, it becomes an archdemon, boosting its speed and equipping it with iron weapons. The status of archdemon also grants it a super ability, in which it reveals its wings and cannot be damaged while charging an attack. The attack creates an area of effect shockwave that will hit entities up to 10 blocks away. Demons also use their common ability granted by their class, detailed below.

Classes
A demon warrior has a class which determines its appearance and ability. There are six of these that are all equally common.

Scourge
The scourge class is a red-armored, black-masked demon that bears a flaming whip. The attack can be recognized by the conjuration spell "Flagellum flammae!" and deals 5 hearts of damage while setting its victim on fire for six seconds.