Rider

to speak about that .. if the user is Goggles, Rider will act more... warm. okay, still an asshole, but less grumpy and actually listening... like a tsundere! he'd act as if he doesn't like him... but he does. a lot.

In the beginning, Rider is stern, no nonsense, and is convinced that if only he wins, his team will win in the end. Upon meeting Goggles, he looks down on him and snubs him off (as Rider at the time was A+ and Goggles was and still is C-) to be weaker than him, and continues to mock and belittle Team Blue. Afterwords, he opens up to the idea of a "one player is all" mindset is not the way to go, and works hard bettering himself and treating his teammates with respect, rather than treating them like nobodies picked out of the crowd.

In the present day he is much more relaxed and act like he has a cactus up where the sun doesn't shine (he obviously doesn't. it's just a way to say that the character is an ASSHOLE), and is more open to criticism and is seen planning with his team thoroughly, as seen in the tournament arc in Splatoon 2. However if someone brings up his past or if someone requests that he do something that he knows he doesn't like, he will become grumpy and hostile, but will do it anyways within a reasonable timespan. he's the same age as the Team Blue's members.

Rider's full name, "Raiden Rockenberg", was given to him by Yoshikawa in a livestream discussing the 'anime'. Rider has become a bit of a mentor to Team Blue, and has their contact information saved in his phone.
It is hinted multiple times Rider has romantic feelings for Goggles. According to the Inkling Almanac, he takes great pride in his Dynamo. This is enforced when he picks up a part time job at Sheldon's weapon shop as his knowledge of weapons even impressed the horseshoe crab. he now takes the time to appreciate his team. he is... now more mature. he is the only heir of the Rockenberg company.

Rider has the typical characteristics of an inkling, a round face, pointed ears, an eye mask, and sharp teeth. He is depicted with black skin, the topknot hairstyle, thick eyebrows, the loose denim shorts, and yellow-green eyes and tentacles, although he can change his tentacle color at will. Throughout the series, he is seen wearing Fake Contacts with the Black Inky Rider and the punk boots. in Splatoon, tentacles ARE their hair. they don't have any corporal hair due to that, causing their skin to be all smooth and cute. it applies to all inklings.