Definitely Shadow the hedgehog. His character has a lot of deep back story and is kind of a refreshing change of pace for me. The fact that he is more of a neutral character also give an extra point in my book. Also, I just love his color scheme.
Old news but I gotta say, when we were still getting trailers for Sonic Forces, I was getting pretty hyped for Infinite. The speculations and theories on his true identity and his connection with Sonic were setting him up to be a memorable character. Sad to see him fizzle into nothingness like most other Sonic enemies.
Looks like Merlina still rains supreme as my number one Sonic character <3