While you were collecting samples for me, my experiments led me to realize that more reagents will be required for this new disease to spread properly. Poisoning some hapless victim is child's play. Plaguing an entire world proves to be a bit more complicated.
I will need 5 Vile Fin Scales from Murlocs in the vicinity. You will find the creatures along the coast to the north or to the west.
The scales are perfect, <name>. Exactly what I needed for this concoction.