Metal Sonic.

Metal is someone who, despite being a robot, has his own personality and makes his own decisions. He generally has a serious and calculating behavior, he is cunning, since after all he is a detective. Curiosity as such is one of his qualities, since he often feels interest in new or suspicious things for him. He is neither a hero nor a villain, he does things his way like an anti-hero, but he becomes selective and thoughtful in his actions. His same cunning allows him to be someone who knows what his path is and to be someone conscious, grateful and occasionally friendly. Although he also does not avoid being bad sometimes, and with bad, he refers to violent in some cases that are almost always.

Metal Sonic is a blue metal robot, a gray metal "bear" with a pointed nose, triangular ears, on his chest he has a kind of propeller with which he can move and propel himself quickly, his hands end in claws and on his shoulders he has sharp metal shoulders that are part of metal. The sclera of his eyes are black and his irises are red.

It was created as a search and rescue robot, but it also decided to become an independent detective.

-use of firearms.
-hand-to-hand combat.
-cunning.
-ability to manipulate.
-can quickly learn the skills of his enemies (copy them)

(I invented the AU so many things change)
Metal Sonic was created by Mr. "Ivo Robtnik" with the purpose of being a detective or help robot for this. But in an unsolved mystery, he disappeared leaving Metal Sonic with multiple doubts about his whereabouts. Thus, he is still dedicated to doing what he was created for.