A focus... such as a wand. It was very, very different from what sorcerers were like in Skulduggery's world - for one thing, female sorcerers didn't differentiate themselves - and yet, he was fairly sure he'd met at least one who insisted on waving about a long thin stick while using magic. It was bizarre.

"And as a sorceress, what can you do about this barrier on your own?" It wasn't an accusation; more of a polite and honest inquiry. Skulduggery clicked his fingers to summon a flame, speaking without waiting for a response. "What happened when you tried touching it? Did you try putting your hand all the way through, or did the barrier act like a solid wall?"

He grew the flame into a small fireball and sent it flying towards the barrier. It hit and scattered, just as he expected it would. What Skulduggery didn't expect was for the flames to scatter back out, towards him, and about twice as strong as they were before.

As an undead skeleton, he didn't even feel the need to move out of their way.