Yu Yu Hakusho1992

[Kuwabara wonders aloud how Shinobu passed through the Kekkai Barrier unharmed]

Shinobu Sensui:
As you remember, MY energy is of the sacred kind. Fortunately the brains in Spirit World only made this net to filter out demon energy. That's why I pass through unscathed while Hiei's attack burned out when it hit the net.

Hiei:
[to himself] If my best technique can't even singe his ass through this fence, how are we supposed to fight him?

Shinobu Sensui:
But you and your friend should take some consolation in the fact that THIS Kekkai is only sensitive to the energy of A- or S-class demons, which means that, in killing your friend, I've awakened the potential you've both dreamed of. Your silence is all the thanks I need. Ironically though, now that your powers are finally strong enough to match me, you can't get close.