Venators: Legends Rise (Venators #3)

The path will be forged in sweat and blood.
Rune, Grey, the shape-shifter Beltran, and willful vampire, Verida, set out to rescue their friend and mentor, Tate, from the gladiator games. But first they must navigate the perils of Eon and its warring factions. Each of this band of four carries with them a secret that threatens to tear their group apart from within. Rune now bears the mark of the promise she made to save Grey's life - a nixie bubble lodged in her arm that could call her away to do their bidding or spell her death.
Even as their loyalty to their cause and to one another faces its greatest test, Rune's twin brother Ryker is forging an alliance with their mortal enemy, the powerful sorceress Zio, who has plans of her own for the Venators and Eon.
Hearts will be bared, secrets unveiled, and relationships made and destroyed in this stunning new installment of the Venators series.