>>527973202
>>527973332
>>527973423
"Even if my memories are not my own, it's still me, Shadow. I will fulfill my promise to Maria...that's the only thing that matters to me now."

The Biolizard represent pessimism; it carries the false delusional will of Prof. Gerald, a tool of revenge. It doesn't have a will of its own it was engineer as a vessel of revenge, which syndicates Gerald's insanity of wanting revenge against humanity who took maria and his colleagues from him. He became nothing but a husk of his former self, only driven by anger, pain and despair. The Biolizard was a failed experiment not only because of the poor life system but it symbolize Gerald's failure.

Shadow represent Optimism: He was created with a soul and he's the embodiment of Maria's dying will to protect humanity. He was seeking a purpose in his life; he thought he was carrying Gerald's wish, but instead his real purpose was to keep humanity happy even if they're against him. Shadow is a guardian, willing to fulfill maria's promise and everyone's wishes of a better tomorrow.