Liu Chan actually died of natural causes. After surrendering, he was relocated to Luoyang, and enfeoffed as Duke Anle. Also, it would have been suicide for him to try and defend Cheng Du (not Baidi castle, btw), since he had virtually no forces - they were all with Jiang Wei.
Rakiri's right, Zhou Yu died of natural causes, albeit at a rather young age. And yes, we are discussing Lu Su, not Lu Bu. Learn to read. Also, Lu Bu was executed by Cao Cao precisely a decade before the Battle of Chibi.
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Signature credited to Nathan (or whatever he decides to call himself next)MSN address: yamiken (at) hotmail (dot) co (dot) uk
[size=6](You know the drill, remove the spaces, replace the at with @ and the dot