Quests that begin here can be found listed in the Ember Isle quest series.
The Teleport Urn at ground level in the south tower takes you to the top where there are 4 catapults. A sparkle in the air shows where the shot will explode. Wait for the drake to appear and lead him, considerably. remember the catapult takes time to wind up. There is no way down, so if you have a feather fall trinket, use it (2200+ dmg without feather)!