To start,
Jetts get a link skill that gives 6% more time to a summon'd familiar (monster cards)
Battle Mage get a link skill that gives 10% more crit
Mercedes get a link skill that gives 10% more exp when killing monsters
Cygnus / Explorers get a "Blessing of the Fairy that gives +1 per 10 levels for explorers and every 5 levels for Cygnus
As a Dual blader, your main mobbing skill is complete ownage, then you get a move were it looks like a cart wheel and you hit everything around you.
Jetts get a turrent, alot of mob skills and good mobility, and 8% HP recovery every 5 sec or so (great for starting = less on potions)
Battle mages, decent damage unfunded imo
Mercedes you cant make right now
Cygnus are strong and i think max level for them is 120
I would suggest making a Jett as a first character to save on potions, on top of professions you craft your gear/potions