The Void Monster Egg can be found in the Shop. It costs 
215 if bought from the Shop. Other ways of getting Void Monster Eggs are through special roulettes, completion of specific collections (requiring Mystic to Ragnarok Monsters), which award 1 to 4 eggs respectively, or as a rare reward from the Mysterious Mine in batches of 1 or 2.
The egg comes with a 97% chance of an Eternal monster and 3% chance of a Divine monster being hatched. During Void Monster Egg events, the chances can be modified anywhere from 70-80% for an Eternal monster and 20-30% for a Divine Monster.
For more information on what monsters appear in what egg at each level, visit Egg Levels.
Trivia[]
- During a Lucky Roulette event, there was a bug where players could gain many Void Monster Eggs. This was quickly fixed and a rollback was issued to all players. As compensation for this bug, all players received a single Void Monster Egg, which stayed in the gift box for only one day rather then the typical seven.