Pain.
Katerina had never thought she would one day be in so much pain that she couldn't move. Even when she was hit by a tank shell in the Middle East, she hadn't experienced such intense suffering. Her brain was completely dominated by the pain, losing control over her body.
By the time Katerina had somewhat recovered, she still couldn't get up; only by curling up could she manage to lessen the pain in her stomach. She breathed carefully, puzzled by what kind of attack she had encountered, and slowly took out her phone with her right hand to call Okayama Buji.
"Hello, what's up?"
"Dio has come looking for us, hurry over."
"What?! Okay! I'm on my way!"