When Leona dismisses Crowley’s idea to retire Malleus in Book 2 Vil agrees with him, and they are simultaneously competitors and allies during Phantom Bride when they both become motivated to show up Malleus.
Vil adopts new speech patterns to appeal to Eliza during Phantom Bride and Leona reacts with “I’d take the regular you over this slimeball.”
When Eliza compares them to Idia they both insist they are “obviously superior”, and Jade observes that “They’ve lost sight of our objective”.
Vil agrees with Leona again in Book 6 when Leona expresses a desire to turn Idia’s hair to sand, again when Leona decides they ought to help a STYX staff member to force his cooperation, and again when Leona suggests that the first person to reach the Underworld gets to beat up Idia.
In Tartarus Vil reiterates this, saying that he “MUST reach Idia and Ortho first so (he) can give them a good slap on the face.”
Vil seems to have little patience for Rook inserting himself into Leona’s business: we see Rook looking for Leona during a class, and when Vil expresses displeasure Rook responds, “You don’t need to feel threatened”.
Vil gives Rook a warning: “While Leona is little more than a good-looking layabout, he is quite troublesome when angered. Do not let your provocations get out of hand.” Rook asks, “Is that an order, sir?”, and Vil responds, “You’re welcome to take it that way”.
Vil encourages Rook to join the Spelldrive club if he is so desperate for time with Leona as Leona is the club captain, and tells him, “I urge you to exercise discretion and ensure that you do not lose (the vice housewarden) seat…because I would replace you immediately if you got our dorm into trouble.”
Twisted Wonderland Reference Note 