Vouli,Vouli, Velzevouli

Yep.
It's Voulis' Beelzebub face.

はい。Vouliのベルゼバッブ顔ですｗ

OR IS IT A CAT DEATH VOICE IMPRESSION?

むしろ。。。。ネコデスヴォイス？！ヽ(ﾟ◇ﾟ )ﾉ