The easiest boss for me is the final boss. I didn't even care about if my friends died until the last part when I had to bring them back so I could use magic on the rings. xD

The most annoying boss was the friggen Malbaro. (I think?) That one was so annoying. I kept getting poisoned over and over. I was like. "Screw this!" xP

old crab is easy and fun for me

yea, the malboro one and the giant fish got me mad...but i finally beat them!

The fish is easy as long as you don't expect to be wailing on him all the time. This also goes for the malboro, patience is the key to success with these battles. The Crab gets nerfed big time in multiplay since you have to fight in the miasma so he's pretty much a push-over. The scorpion and Bird are stepping fights where you dominate their crystals. The komodo dragon (rider) and the behemoth are just a basic full out kills which are rather fun and easy to read.

Then you have the hard stuff...

The crystallized Alhanalem can turn out rather bad if you don't learn to pick up the fire magicite he tosses out. Which means if you get stuck in a loop, you may only get off ~2 strikes before having to pick another one up. Trust me, in Very Hard mode, his stylus thingy HURTS (I love using it though since it deals 4k damage every 2 seconds to whoever is standing in it).

The Lich, while not hard when you figure out her range, is rather surprising at first since it is the only enemy in the game which can Doom you, and her spells aren't "slow" like the others and require quick movements to get away.

The temple acolyte guy can be annoying too since he has no weak spots, halves the damage you deal, and can split into 3 and chain you to death.

Last but not least, the hardest boss is definitely the Crystal phase of the Temple High Priest's last form. Along with the boss casting "stun/knockback" spells which do frightful damage, about 6 or 7 crystals are all casting spells as well which can potentially lag or interupt whatever items or spells you try to use. Essentially, it's a boss fight where you shouldn't focus on killing the quickly respawning crystals, but downing the boss to 50% health so that you can quickly move past this irritating phase. Quick charge attacks and little pecks are about all you can do while avoiding all the spells going about.