Battle Angel Alita: Mars Chronicle Vol. 4 (manga)

Erica is now under the tutelage of Baron Muster, who has taken it upon himself to school her in the ways of villainy. Erica displays an uncanny knack for being bad, making her the perfect pupil, but her young mind and fresh perspectives also prove to be a boon in Muster’s search for a legendary Martian treasure. With Erica’s help, Muster and his team make it to a secret labyrinth that houses the famed treasure, but before Muster can finally get his long-awaited prize, an unexpected turn puts everything into jeopardy …