How do I complete Billy's promotion event, 'A Hairstyle's Importance'? September 26, 2025 07:22 Updated With Billy as the team leader, enter the Hollow Zero.Explore the area and trigger specific events within the hollow to complete the commission. Related articles Why is my game progress missing on Xbox, and how do I link the correct account? Minimum device requirements for Zenless Zone Zero Why can't I get the TreCarls Film Case for Lucy's trust commission? How do I find or trigger the 'Behind the Curtain' quest? My HIA Commemorative Coin collection progress stuck after interacting with the NPC Kaibara in Ballet Twins Road.