Mavra trained Bianca in magic to help her get revenge on Harry and she was also responsible for one of the most successful attempts on Harry's life - the flame thrower attack that was designed to get around his shields. If she is Grey Council, then the Grey Council is black. Also, Eb dropped a meteor on Ortega for trying to kill Harry, I don't think he would deliberately let Mavra walk away unscathed for the same offense.
I recently saw someone theorize that Mavra's goons didn't use weapons in the altercation involving the Vampire staking by turkey because the purpose of the altercation wasn't to kill him but to manipulate him into teaming up with Lara. When I wrote
my list of Harry Power Ups long ago, I couldn't help but notice that Mavra's "attempt on Harry's life" didn't just result in the blackmail material that drove the plot of Dead Beat, but is directly responsible for the motivation for some of Harry's most impressive magical development in the series summed up by these bullet points from that post:
- BR: Burn trauma stunts Harry's ability to use Fire Magic PD
- DB: Starts moving things using directly applied Force/Will rather than Wind RP/Sk
- WK: Crafts his new Shield Bracelet which blocks more than force/physical, particularly fire Sk
I can't help but wonder if she was working with Lea in that altercation in order to force him to branch out and pursue magical skill beyond his fire standby.