"Sapphire Flames: A Hidden Legacy Novel (5) by Ilona Andrews

"Sapphire Flames: A Hidden Legacy Novel (5) by Ilona Andrews
  https://www.amazon.com/Sapphire-Flames-Hidden-Legacy-Novel/dp/0062878344/
Book number five of a six book and one novella (seven books total) paranormal romance fantasy series.  I read the well printed and well bound novella MMPB published by Avon in 2019 that I just bought new from Amazon.  I have the other two books in the series and will read those soon.
Totally cool series for me.  This makes the fourth series that I have read from Ilona Andrews, a husband and wife writing team based here in Texas.  The Innkeeper, Kate Daniels, and The Edge are the other series of books.
The Hidden Legacy Universe is a complex place.  The Osiris serum that induced magical powers in humans was released to the general public in 1863 and the world was never the same.  The Osiris serum has three results: death, paranormal powers, or paranormal powers with a warped human body.  The serum was banned after a while but the world was irreparably changed since the paranormal powers are inheritable. Families starting breeding children for strength in magical powers with breathtaking results.  Magic users are segregated into five ranks: Minor, Average, Notable, Significant, and Prime.  The Prime families operate mostly outside the Federal and State laws since they are so powerful and incredibly dangerous.
Catalina Baylor is Nevada Baylor's younger sister and a Prime Siren. Nevada is wed and gone so now Catalina is running the show.  And now Linus, the long term friend of the House Baylor and former speaker of the Assemblies of Magic, has revealed himself to be the Warden for the State of Texas and is making Catalina his only Deputy Warden.  Because, somebody is making Osiris serum available again and the results are mostly warped humans with paranormal powers.
Arabella Baylor is Catalina Baylor's younger sister and a Prime Beast that is unknown to the general populace.  She can transform to a 65 foot tall beast but, she has trouble controlling when to transform.  The only other recorded person who had this power could never control their transformations or reason while in beast form so the populace is incredibly scared of her.
Alessandro Sagredo is a Prime Weapons Teleporter, an Italian count, and drawn to Catalina.  And a assassin for hire to the highest bidder.  He says that he is going to protect Catalina against the bad mages but he has a hidden agenda.
The authors have a very active website at:
    https://ilona-andrews.com/
My rating:  5 out of 5 stars (I am starting to think 6 stars)
Amazon rating:  4.7 out of 5 stars (10,331 reviews)
Lynn