Well...
Vulcan proved he can manipulate magic.
From the other hand, Gabriel failed ina HARD way in manipulating the energy of sun-dipped Havok. That means, his manipulation power range is fairly limited.
With that said, he lacks cpacity to affect Cain in any way that will save him from curbstomping.
Title of Emperor doesn't stop the Juggernaut!!!
Originally posted by Bentley
Forcefield by manipulation, the helmet prevents psychic attacks, not manipulating brain waves by physical means.
He can't manipulate his forcefield, he lacks the feats that suggests he can bypass Cain's shields. You can't enter his brain at all when the helmet is on. You can't attack him, read his mind or anything.