For those who don't already know them I'd like to introduce:
ONE OK ROCK
I'll just let their music sing for itself .
「Keep it Real」 is one of their first songs before their official debut in 2007.
「The Beginning」, their hit song that's used as the theme song for the Rurouni Kenshin movie.
Check out their official youtube channel for more videos.
You can even buy their songs on iTunes.
Or if you're like me and prefer to have your music in physical form, I can recommend cdjapan.co.jp.
Bonus song!