The bosses in the Sword Kings place in FFXII are total pushovers compared to Tiamat or that Elder Wyvern. The first one(the one with magnetic field) is just a "hit it until it dies" boss, the second though is another matter entirely. The best thing to do is to target the boss itself and let-rip with a Technick chain(at least 4 should do). After that, mop-up any of the minions that are left(they're immune to fire), and then pound away on the boss until it dies. The rewards for the battle are well worth the effort.
