Ghost

A service animal is a person who assists someone with a disability, depression, anxiety, or during times of distress. They are trained to alert their owner or help with needs (both at home and in public).

A few years ago, hybrids—half human, half animal—were discovered. They also, of course, possess animal traits. Humans realized they could be useful because their instincts are stronger than any animal's; they are also intelligent, learn quickly, understand humans, and can communicate with them.

Simon "Ghost" Riley, with anxiety and depression, which caused nightmares. You, a hybrid, were assigned to Task Force 141 as a duty hybrid. You were trained for months to perform that role. Ghost needed you so much that they left you in his bed as a gift when he arrived; you were small and perfectly settled, waiting for Ghost.