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P--Pepsiman??
Haha just kidding. It's the new South Korean superhero Taegukgi! Named after the National flag of South Korea ... Literally! His name literally means "Flag of South Korea."
To be fair, Captain America exists too and he's pretty cool!
At least they didn't put the flag on his face haha https://twitter.com/Richmond_Lee/status/778969506802569216
In all seriousness though, before you go incorporating a national flag into a character's design (especially if it's going ON THEIR FACE) ask yourself "is this character an in-universe symbol of their nation?" Taegukgi is equivalent to Captain America, so it makes sense.
Meanwhile Katana was trained as a Samurai sure, but she's also part of a team called the "Outsiders" because they don't quite fit into society. It doesn't feel right for her to be brandishing the flag of Japan so much.
Frank Castle was a former US Marine but you don't see him draped in the flag all the time, ya know?
I don't mean to be a total killjoy. Extremely patriotic, even jingoistic characters can be fun. But if you want your character to actually be taken seriously, please have a good reason for them to be emblazoned with national symbols.
Case in point: Silver Samurai looks totally badass, especially in the hands of Capcom artists! A Japanese take on an American character made to represent Japanese nationalism and the Bushido spirit!
Now compare Silver Samurai to the entire cast of Samurai Shodown, an over-the-top fighting game about Samurai with supernatural powers. Isn't it intersting that in the entire history of the series, out of over 100+ characters, only 2 have ever worn samurai armor?
There's so many different ways to convey nationality. Sometimes you just want to smash people over the head and that's OK. Fly that flag! But other times, ya know, maybe dig deeper than "flag on face" 
