When Grand Chase meet him, he is possessed by something and is drinking all the water of his Fen. Guang appears to be resisting towards the Darkness, and tells Jin to run (who seemingly doesn't respond to this due to his rage). They start running until they are forced to fight back, where Jin advises the Head is the Weak Point.
Once they defeat him, King Guang thanks Jin for saving him, then fades away as the water is released back to wherever it came from. Before he dies, he asks Jin to avenge him as his final wish. Jin is sorrowed, shouting his name in tears, but his comrades convince him to let go of his sorrow. The group proceeds to avenge King Guang so that he may rest in peace.
He has a friend, King Fang (though ironically they both look identical). Upon a "messenger" delivering the news of Guang's death, Fang becomes outraged and wants to kill his assassins, hoping to avenge his beloved friend. He was deceived as the messenger brought inaccurate information, where as Guang let himself fade away rather than being slain.
While in battle, King Guang is generally in the middle of the screen, stationary. It should be noted it is impossible to go through him with Arme's "teleport" or the Crossbowman's roll. The only way to get behind King Guang is to go up the platforms, though he will usually turn to face the player, and sometimes knock his foes off as he spins.
King Guang is known to bite and slam his tail down to produce an earthquake. His main attack is firing a water flame attack. The flame attack fires in a different position depending where his target is. It should be noted the crystal saps the player's HP and/or produces property effects that while on his back. He will sometimes shoot a sphere that fires up, then scatters into smaller spheres amongst the field.
In order to deal full damage to Guang, you have to hit his head. His scales reduce all damage provided to 15%, while back attacks substitute for 30%.
- Unlike others that were corrupted, Guang is the only one that still has possession over his mind. It could be possible that the Ascendant God had trouble possessing him.
- He is the only creature that has some sort of passive protection enabled to defend himself, specifically his scales.
- Ironically he looks almost identical to King Fang. It is believed that they may be cousins or brothers, not friends.