As you "download" them to your side, the rival is alerted, creating a frantic "Escape the Lair" sequence where you must protect the monster girl while she’s still "decompressing" into her full form. Why it works:

Since the title references a compressed file ( .rar ), the core mechanic could revolve around the monster girls from a rival’s digital or magical vault. Feature: The "Data Siphon" Heist

Instead of just winning a battle, you have to strategically "extract" the harem members during high-stakes infiltration missions.