Battler: That head is pretty awesomely carried out, and since he's animalian the unarmored limb pieces work out. The claws are a pretty nifty design as well. I don't like the way you attached the Bohrok eyes onto the arms, and I think he needs more Mata Red in his torso/shoulder region. That, and take out the random trans-green armor piece. If you wanted to seriously work at improving him, you could take out the gunmetal armor on his other arm and torso as well.
Grottor: Color layering is pretty nifty, try to do stuff like that more often. Can't say that the way you did the feet worked out the way you intended it to be, and the armor/spike placement in the torso is quite random. The trans blue piece on the torso armor also seems a bit random.
Stalactick: Again, the attempted feet designs don't work out, but I like what you did with the torso.