In Wang Yuàn's ear, that statement of 'I am your brother' sounded exactly like 'I am your great ancestor'.
After all, if a stranger suddenly appeared in your house and told you something like that, anyone would react like that, assuming that they're joking or trying to rile you up.
However, Wang Yuàn's mind was sharp. Even though her parents hadn't told her any details, she knew that she had a missing older brother from before she was born.
Could it be him?
Why did he return?
Why does he also have power?
Is he a member of the Infinite Room, or the Nightmare Space?
These three organizations frequently clashed against one another in Mission Realms, as an appropriate level of competition was beneficial for the overall development as a whole.