Before becoming Grimstone he was Kakuryu a member of the Decepticon Dinoforce. He was the dumbest member on the team hopeless, clumsy and kind. It was unknown why he was a Decepticon buthe he eventually joined the Autobots and become the Dinobot Grimstone.
Grimstone has always dreamed of power and the privilege it brings. Despite his hunger for power, however, he has always considered the needs of others before himself. He believes it is the responsibility of the powerful to protect those less fortunate - a belief he intends to aggressively enforce now that he has his own Power Core team.
When Grimstone and his team combined together they become Grimmaster.
Power Core Combiners
- Grimstone with Dinobots (Commander Class, 2010)
- Part of the fourth wave of Power Core Combiners, Grimstone transforms into a Styracosaurus. He also has a third super-robot torso mode compatible with all Power Core Combiners drone-limbs, though his nominal combination is with his packed-in Dinobots drones. He also has a Mini-Con Powerlinx hardpoint on his tail-tip.
- Wave 4 only barely made it out to normal retail at first, meaning most fans had to get him from online stores. At the latter half of 2011, the later Power Core Combiners 5-packs started showing up at discount chains like Ross, TJ Maxx and Marshalls.
Power Core Combiners Special Value Offer
Grimstone and the Dinobots were made more readily available at retail as part of a Walmart-exclusive Black Friday value pack, combining a 5-pack team with a Commander 2-pack via packaging tape and a couple of stickers, and costing all of ten dollars.
- Grimstone's box misidentifies him as a Triceratops.
- Grimstone's airbrushed prototype stock photography depicts his super robot mode's helmet/dinosaur head having a slightly wider gap between its nose and eyes compared to the less separated "cracks" of the regular robot mode, suggesting there was once an additional joint that allowed his dinosaur nose to slide out and separate/extend ever so slightly from the rest of its face.