There was a brief flash of memory at the notion of being surrounded on all side by monstrous enemies, of seeing ice and magic fly around the field of battle while he sword struck flesh and spattered warmth into the air. It was reminiscent of the time she'd spent on Jotunheim, after her exile from Asgard and, were she to be honest about it with herself, that t'was not at all a memory she relished. What it was however, what it would serve to be in this moment at least, was fuel for the swing of her blade that would follow Harry's command. The strike was hard and true, leaving fragments of once lumbering beast to go sliding beneath their feet as Sif stepped up into the gap it had created and continued to press back against the wall of flesh.
A quick swing of her shield arm would dislodge a one of the leaping corpses from it's plan of launching itself onto either of them and Sif was quick to follow up the shunt with another firm strike of her sword into one of the more bulbous looking creatures behind it. A grunt. A breath. Sif kept her eyes forward, doing her best with those who were advancing with them to press through the swarm.
"Frost Giants they are not, but your fire magics work well!" Sif finally returned a chime of her own, taking advantage of a brief opening to slot the hilt of her sword into it's second blade and toss her shield into the groove at the back of her armor. With the sheer number of foes, even if the shield would have offered more protection, Sif was more interested in getting more reach behind her strikes, to keep the things at a distance, as well as make it easier for arcing motions to be follow by forward steps...
Plus she saw another of those things, Ravagers they'd been called, and she wasted no time swinging the blade to upend the creature and send it scattering backwards into the advancing horde.
"That one, with the blood that burns!" She gave the best point she could. "Might you have a magic that could turn its weapon against it's allies?" Because if Harry could conjure spells like he had been, Sif reasoned it was possible he could make the thing explode, and acid pouring through this advancing rush just might by them so more ground toward their goal.