Why is Starughan also known as Ripusudan?

Why is only Starughan known as Ripusudan and not all brothers ? If anyone know abt this then pls share it ...😊

The name I heard was Ripudaman. From what I heard, though I have not read this anywhere, reason he got this name was for killing a rakshasha named Ripu when he was very young - probably around the time Rama killed Taraka.