Here's a hint for those struggling with the 15th Floor Achievement.
Start off with an Atlantian Magus and pump skill points into Will until about you have around 50-60. Frozen Wind and Ignite should take care of most enemies (I prefer Frozen Wind due to its low MP cost) and if you find an item with Bolt, keep it. Bolt is amazing at killing individual enemies and you'll find it useful up and until around floor 12.
If you find any armor with Ice Resistance, keep it and don't sell it. Why? Once you get to around floor 12 you start getting ambushed by groups of ice-based enemies using charge. The good thing is if your Ice Resistance is over 100, any damage that would have been done to you is instead converted into Mana. Just have Frozen Wind on one hotkey and you won't have to worry about damaging your MP suppliers. Heal is also handy to have.
Please plus if this helped you ^_^
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