The Mobs in ROM
You can tell what type of mob it is by viewing their target info in the upper middle of the screen. Mobs are placed in three categories, Regular, Elite, and Crown Bosses. Regular mobs have just a level (Rom Gold) by their portrait. They can be killed by a solo player or in groups with ease. They drop trash loot most of the time, but every once in awhile they drop white or green gear. Very rarely do they drop blues or purples.
Elite Mobs have a gold eagle border around their portrait and their level in aion. They also can be Quest Bosses too. They are stronger and best taken out with a party of at least six members. They drop white and green gear, rarely blues, and most inhabit a dungeon or instance. Crown Bosses are the hardest.
They are noted by the golden eagle border and instead of level (ROM Gold) number, they have crowns instead. Some have bravely beaten them with just a party, but takes awhile. These mobs have a load of HP and have high damage output. It's best to take a raid party of 20 or more people against these. They drop white, green, and blue gear a lot and sometimes a rare monster card.