The Child's Twins?

"What's with that look? It feels like you just see a ghost or something. Wait, is there something on my face?"

The boy did not answer Tornado's question and instead, he raised his index fingers and pointed at something beneath Tornado's legs.

His fingers were trembling greatly. 

"What… What are you doing!" The kid raised his voice as his mouth was trembling.

"Killing an enemy of humanity, why are you so afraid?" Tornado asked. The kid was not afraid when he killed those zombies yet why did he become like this all of the sudden?

Tornado then looked down, following the boy's finger, and found that the mini-boss was gone!

Correction, it was actually greatly decreased in size and Tornado has to move his eyes slightly up.

Changed to a headless child wearing white cloth on top of a pool of blood.