Incest

From a divorce, twins Minato and Rui finally met after 15 years.

2nd to the last chapter includes a twins, Jens and Hans working at a circus

Real brothers shounenai

Step brothers ever since they're kids

Tiniest, Toru, who always stutters went to make friends his mother paid to play with him but, its obvious that they didn't liked him. Years passed he became a hikkikomori while his little twin brother Satoru diligently went to high school. By the time Satoru graduates his wish is to live independently with his twin. Little did he know that their mother abuses Tooru and that made him violent.