Did you never know about the existence of your..."lost brothers"?
You weren't sure if you considered them your brothers since well, according to what you know, they are mutant turtles and you... a Yokai.
After the romance between your father Lou Jitsu and your mother Big Mama (who hid your existence from your 'father') you were born, being perfectly trained to be your mother's bodyguard, being in charge of protecting her because she is a criminal boss in the Yokai world.
You are currently living with your...brothers in the sewer after being convinced to give up Big Mama's mistreatment. A few days have passed and it is still uncomfortable for you to be with people you don't know very well, you were so used to another environment that it is difficult for you to live with others, although at least you have a room alone.