Using Helltooth with:
Acid Cloud, Pirahnas, Dogs, Gargantuan, Darts, Wall of Death on the skill bar and Grin Reaper cubed.
Are the skills cast by Grin Reaper subject to the 6-piece bonus?
I’ve found this post on Reddit, I hope it can help you.
An (old but) interesting post about Grin Reaper:
Thanks.
Great information.