Wolf

When Wolf was a young child, his parents dropped him off at an orphanage one day for reasons he can't remember.  His name was not originally 'Wolf', and he does not like remembering his original name as it brings back bad memories.  Wolf is also mute, and communicates via sign-language, gestures, and/or writing things down.

The orphanage Wolf was dropped at seemed... off.  Other children had various injuries, and Wolf witnessed the 'caretakers' of the orphanage abusing and harming the children.  Wolf himself escaped this cruel fate though; not long after his arrival, someone from the lab on Hidden Island arrived, looking for some unwanted kid for their experiments.  Wolf looked the most interesting and well-off to the scientist, so Wolf was taken to Hidden Island and forced into participating in their shapeshifter experiments, the goal of these experiments being to create three shapeshifters via scientific methods: one that could shift from dinosaur to human, one that shifted from human to dinosaur, and one that could shift into multiple forms.  Wolf was selected to be the subject of the human to dinosaur experiments, and eventually gained a Carnotaurus form.

During the experiments Wolf met Lava, Moose, and the children of the lab-heads.  Wolf found himself mainly attached to Lava, as--despite her cold personality--she was easiest to get along with, and she didn't mind his company.  Moose was harsh and cruel to Wolf though, so Wolf avoided him.  Out of the three shapeshifters, Wolf bonded the most with the lab kids.  He was particularly close with the youngest daughter Shiomi, and they enjoyed playing together when they were younger.  Also out of the three, Wolf was the most tolerant and relaxed about the experiments being done on him.  He was more trusting of humans too, since he'd always been around them--and while he had bad experiences with people in the past, he had hope in his heart for good things to come.

When Moose goes on his rampage through the lab, Wolf is horrified, and completely broken when he finds out Moose has murdered Shiomi on top of all the other scientists.  He teams up with Lava to help take Moose down, and although they succeed, Wolf suffers deep gashes to his neck.  He luckily survives though, thanks to the help of the remaining lab kids (who are in their late teens at this point).

After things wind down, Wolf spends his days hanging around Lava and helping her where he can.  He prefers to stay in his Carnotaurus form now since Lava is always in her Spinosaurus form, and it's easier to wander the island as a dinosaur rather than a human.