Wyrmrider Vengeance: An Underwater Magic Urban Fantasy

Zombie sharks! What the ... ?

It's not the first time I've faced a bokor...
But this dude (or dudette?) is on a whole other level of evil.
I mean, it's not unheard of for bokors to raise zombies...
But sharks? Come on!
The wyrmriders are getting there...
They've been training. We're becoming a force.
But the sharks move like torpedoes... these aren't drag-your-desiccated-flesh-behind-you zombie creatures...
They are fast... think World War Z meets Jaws...
And they're hungry. Their population is growing... if they make it to the beaches... if they bite any humans, any merfolk... who knows what will happen.
But even if we manage to stop the sharks, if I can't find the bokor behind it all, he'll just make more. And I can't figure out what his end-game is...
Will I be able to find him, and stop him in time, or will the oceans fall prey to a zombie-shark apocalypse?