Loki feels no shame in invisibly attacking opponents. Even if they were visible themselves, he'd happily do it. He's quick to go after the invisible one creeping toward Palmer, sliding low and slashing at the back of its legs to bring it down (and hopefully visible), and then rolling away from the main fight.

He doesn't want to get caught up in a blast like whatever it was Delia just fired. He might well survive it, but he's sure it would hurt. Time to reveal his presence to his allies, but instead of simply dropping the invisibility glamor, he circles around the fray and releases two illusions of himself, in typical Asgardian armor. One of them snaps into view close by Sif and gives her an impish smile.

The other is closer to Matt, but of course the visual aspect of the illusion will be lost on him. Loki's fairly exacting in his work, though. There is no heartbeat coming from his illusions, but they make soft sounds as they step in the snow, and they breathe.

They also laugh. Loki's knives carry over only in appearance; the illusions can stab but will not harm their opponents, but they can move through the battle and point out the invisible Fallen by the way they dart and pretend to fight them.

Meanwhile, the real thing remains invisible, preparing a fire spell.