Huuma Shuriken Ranka, if you have a Huuma Swirling Petal[2] carded. Bakuretsu kunai can deal a lot of damage but you'll need high base/job level. Those two are heavy dependent on % variable cast reduction equipment though.
Another way is to make a magic ninja with Izayoi + the respective elemental amulet, you'll need a arch bishop giving you Sacrament (my bad i though Sac was variable cast reduction) and/or % variable cast reduction equipment. If you manage to get a Mikatsuki[1] you'll be golden.
I would say do all Eden quests for your level or make a route, see how much time it takes you to complete a quest so you can make a rotation, so by the time you finished the last quest you took the first one is getting out of cooldown, this way you can avoid things like going to Thanatos tower 7. Do the nightmare pyramid quest, they are piss easy and give a lot of job exp. Do the Prontera board too since most of them coincide with eden quests.
Edited by Watermelony, 28 February 2015 - 11:43 AM.