I must admit, Lena always went for destruction spells.

Her big favourite is an updated version of "Baronoff's Bloody Icicle" (30pt frost damage on target) - she added paralysis to it and made it on touch, to allow for a greater impact. Once they are on the ground frozen, she just hacks them in pieces.

She does have protection spells, but... it seems like cheating... after all, a Silencer should be skilled enough not to get hit...

But she uses invisibility to escape if (when) things get dire, and of course, plenty of summons to distract foes. She uses poisons and potions a lot, her alchemy being better than her magic. In the past she also used to like enchanted weapons and developed some very nifty enchantments, but the necessity to recharge those all the time in the end became tedious, and she now mostly uses standard weapons, investing in her agility and blade and marksmanship skills instead.
Oh, and she's got a friend to follow her around... And he's a proper battlemage and normally draws the heat, leaving her free to shoot from the shadows.

To be fair, sometimes he doesn't even get a chance to take up his claymore, because he too starts with summons, of course. (And yes, I did give him a good selection of spells so he could decide for himself what to do. He is very clever!)