see i dont think either really have a flagship character anymore. back in the day yeah, especially xbox, but now i feel like nintendo is really the only one who does. probably because they have much less to offer in variety then the other consoles do
You've clearly not being paying attention to their advertising and marketing.
Halo, Gears of War, Forza and Battlefield (despite not being Microsoft-exclusive) are the big four for Microsoft, with their big icon still being the Master Chief. Recently they've been bringing Tomb Raider into the mix, which works because Xbox is now a brand which encompasses the PC platform as well.
Sony is
really pushing Nathan Drake, but Sackboy was their big mascot for a long time, and before that they were big supporters of Kratos and Crash. Don't forget they funded movies for Ratchet and Sly. And hey, Gran Turismo is amazingly still one of the most successful games on the planet, financially, and they KNOW that.