[@Cu Chulainn] Already reserved for you in the CS Section. 

[@SilverPaw] Wyvern Riders are a Tier 1 class, if I'm not mistaken. Still, to answer your question anyway: I have not yet included it because no characters have been created for now, but the system I will use will award a number of EXP points to players characters for each kills depending on their Level and the level of the enemy they slain. Upon reaching 100, they will level up. At 10, you can promote. In the game, you use an item...in here, we'll handle promotion in IC. The means and the Hows can change depending on who wants to Promote.