Just ran into
this old thread on the OGCC when googling for the black graal (which was prompted by
this "new quest" thread on Graalians by Pr0m4N V.14).
I really liked Tyhm's spin on the idea personally. He also reminisced to having races in the last post of that thread.
I.e. grant a player, or a limited number of players the ability to control the weather in certain areas (e.g. guild towers) as a type of weapon, along with making the player weaker in other manners (e.g. force low HP so long as the player has this power, losing the power when killed).
You know, better yet, make it solely available to players that are not the leader of a guild and have been active members of that guild for a specific number of hours to promote actual guild loyalty.