Cao Yu died in 1996.
Yu Cao has written: 'Jia' 'Wen ji' 'Ming lang de tian'
Cao-Cao was born in 1973.
Fucheng Cao has written: 'Da jiao yu yu xian dai ren di pei yang' -- subject(s): Education
Yes, Guan Yu was fully loyal to Liu Bei. There was an instance when Guan Yu served Cao Cao, and Cao Cao saw the value of Guan Yu as a warrior, therefore he tried his absolute best to keep Guan Yu as a general, offering him wealth, housing, women, and whatever else he desired. Guan Yu, however, continued to tell Cao Cao that if Liu Bei was found, he would immediately return to his side. He only served him because Liu Bei was missing and hadn't been seen, and was possibly even dead. However, Liu Bei was found afterwards, and despite all the wealth Cao Cao gave him, and all the offerings that he gave to Guan Yu, and even giving him the famous red hare, upon hearing Liu Bei's location, he immediately left with red hare in order to continue to serve Liu Bei, he did not have nearly the wealth or riches that Cao Cao had. Short answer: Yes, he was completely loyal to Liu Bei, and only Liu Bei.
Xueqin Cao was born in 1715, in China.
Xiudi He has written: 'Yu yuan shi cao'
Cao Zhiyun was born in 1961.
Lan Cao was born in 1963.
Cao Zhibai was born in 1272.
Cao Dan was born in 1960.
Cao Mao was born in 241.