What is this 'Dimensional chat?'

My name Satria Akbar. I just ordinary man in college with part time job but when I see kid almost got crashed by truck I save him and the result? yes I'am die. I think my life finally over but somehow reborn in uknown world with new identity as Shidou Matsumi , Normal teenager with normal family. [Welcome to Dimensional Chat] [You chosen as admin in this group] [Enter your nick name] [Preparation Ready , Now invite the group member] [Welcome Pervert Sage] [Welcome Evil Spirit] [Welcome Man with Gender Equality] [Welcome Ice Sadist] [Welcome to Dimensional Chat] What the hell is this 'Dimensional Chat'