Here is my guide to the Nelis battle: level up your Main first (get about 60 hp). Get him Vengeance, Orange Orb and Yellow Orb. Level up the rest of the team to a decent level (say, lvl 20). When the battle begings, eliminate the golems and the phantom armors as quickly as possible. Avoid being near the Queen at all costs! After you've done so, position your Main 3-4 tiles away from Nelis,whilst keeping all other units away from her. She'll use Fire Gate on the Main. Use Vengeance to strike back after one or two turns. Sit back and relax when you ran out of PsP, the Yellow Orb should reduce the waiting time, and a healer could use a Long Shield to stay out of harm's way (ie Fire Gate). Meanwhile, whilst Nelis is attacking the Main, you can use other ranged attacks, like Frost Breath 2, Pyro Hail and Dark Vortex to attack the queen from other directions. Another useful find is Niven- get him to deal 50 damage with Trick-shot and you can position him behind Nelis to deal massive damage to her (position diagonally,and she won't attack). Keep repeating the procedure until you win- make sure to keep you units away from the Queen, otherwise she'll use Holy Blast on your teammate, and you'll have a lot of damage control to do in the next few steps.