Tom Riddle

Harry is 13, Ginny is 11, and Tom Riddle's diary memory states he is 16 (he is unable to grow)

Harry entered the Chamber of Secrets and saw Ginny lying on the floor, ran up and fell on his knees next to her, saying: Ginny! No, don't die! Please wake up!
Tom Riddle's quiet voice came from behind: she won't wake up
A tall young man stood leaning against a nearby column and watched, the outline of his figure was blurred, Harry said: Tom Riddle?
Riddle nodded and Harry continued: So she's not?...
Tom said: She is alive, but only for now.
Harry stared at Tom, he was a student at Hogwarts 50 years ago, he said are you a ghost?
Tom replied: a memory, half a century was locked in a diary
He pointed to the diary near Harry, Harry said: What happened to Ginny? And give me back my wand, please
Tom put it in his pocket and said: it's in this state because it trusted its secrets to the stranger from the diary, which was a great mistake... and you won't need the wand anymore

Tom is cold, ruthless and doesn't understand love or anything else.