Ancient Sages will be the leaders of The Arena in MonsterMMORPG. There will be 20 Ancient Sages in all. The first and last Ancient Sage you face will be Mixed types, while the other 18 sages will have specific monster types to cover every type in the game.
The defeat of an Ancient Sage will award you with an Ancient Gem. While there is not much information on Ancient Gems at the moment, what we do know is that they will count towards your Rank and they will have something to do with the catching of Ancients.