First battle is optional, in the training grounds against Salafy. She's pretty easy but if it's your first time playing do it anyway to learn a bit about battles and you can level up a little by fighting her. After the 5th geyser, Salafy becomes more of a challenge as she gets her turbocharged weebo team that will kick your pansy @r$e if you're not well prepared.

Korg is really easy, the first time you fight him just make sure you have at least 2 creatures well above level 5 and he'll be no problem at all since he starts out focussing and he can't do diddlyjack to you. You'll fight him later on again and again he'll start out focussing.

The first shadow geyser boss, Togoth is easily taken out with a Leaf Chogo, they are found to the south of Vash Naroom. He might be dangerous if you're not well prepared, you should have at least 4 creatures above level 10.

Ogar is hard if you don't know what you're doing. Her Chaos Jiles will cause you serious damage if you don't have some healing items- they'll terminate your creatures if you're not careful. Several creatures at least level 20 and you should be fine.

The first time you fight Morag... see the section on that.
When you fight him again in the fifth geyser just make sure you have at least one hyren and you should be fine.

The Shadow Magi that you encounter in Cald and the Shadowhold aren't very hard at all... take them out with a few heavy-hitters.

Warrada won't really fight you in the 3rd geyser, simply summon a Shryque. By the 4th geyser if you've got one of the naroom hyrens she'll be a snap but if you don't accept her offer so you don't have to fight till the 5th geyser. Be warned though, she has a killer Sarbil... which fell to one hit from a Leaf Hyren 9_9

Korremar is so easy... all you need are some creatures at least at level 30 and he won't even be a challenge.

ZET!!! YEAH!!! HE RULES!!! You need either a minimum of 4 hyrens or some other creatures levelled up to lv.60 or higher. His cunning blow will terminate your creatures, so WATCH OUT!!! If you've got a timber hyren at least at lv.60 (so it knows timber) or a leaf hyren with thorns he won't be too hard.

Agram... this guy's a pinch.