When you reach the level cap, you will unlock a new feature, the Philosopher’s Stone.
Philosopher stone
The EXP you receive will then be counted into the stone. When the Philosopher Stone reaches max EXP, it will release its energy and produce massive Gems and even the Philosoper’s Stone Shards. Shards can also be collected by fighting in the Faction War. For every 3 shards you collect, you can get rich rewards. And if you collect 3 shards of the same color, there will be even better rewards.