Lord Voldemort's pet snake and loyal servant
Nagini fact file
Doing the bidding of her master
Killed by Neville Longbottom with the Sword of Gryffindor
The scream of rage, of denial, left him as if it were a stranger’s: he was crazed, frenzied, it could not be true...
Harry Potter and the Deathly Hallows
I think he is perhaps as fond of her as he can be of anything; he certainly likes to keep her close and he seems to have an unusual amount of control over her, even for a Parselmouth.