都叫兽是金秀贤
[dōu jiào shòu shì jīn xiù xián]
The username 都叫兽是金秀贤 means 'Everyone Calls Beast as Kim Soo-hyun'. This appears to be a fan reference to South Korean actor Kim Soo-hyun (sometimes romanized as Siwon). The nickname might play on the similarity between Kim Soo-hyun's name in Chinese pronunciation and his popularity as 'beast' due to roles portraying charming or powerful characters.