The Hero's Immature Younger Sibling

'''Hello? I'm the hero's immature (written as immature but read as ill-mannered) younger sibling. Yes! Just as the introduction said, I'm a twisted, out-of-touch, self-centered, ill-mannered, immature younger sibling! You ask why the younger sibling's personality is like that when the older brother is a hero!? "Brother... where are you going at this hour?" "The princess of the castle has been kidnapped. I'll be right back, brother." "Can't you not go? I don't want to be alone......" "Ren. Everyone is waiting for me." "I'm... I'm waiting for you too, brother! I've been waiting every day!!" "Ren, be good. I'll be back." Even on my birthday! Even when I was hurt! Even when I was wri...