The sister of Manchester bombing victim Martyn Hett aced her GCSEs despite sitting them just days after he was killed.
Nikita Murray's brother, Dan, said on Twitter he was "floored" to see the pupil preparing to leave the house and sit exams "the literal day after we found out about Martyn being killed".
He said she was determined to take the tests despite being told her predicted grades could be used to calculate her final scores.
Mr Hett announced his sister had gained 11 A* grades and said he had "never been more proud or amazed by anyone".
He said: "My little sister Nik is an actual hero. skip back to the literal day after we found out about Martyn being killed.
"We were obviously completely numb, fried, drained. We'd been through something absolutely unreal and were all trying to figure it out.
"I came downstairs, and Nik was sat on the stairs in full school uniform, tying her shoes. I couldn't understand why.
"I didn't even know what day it was at that point, it had been such a horrific few days.
"She was putting her shoes on so she could go and sit a bunch of GCSE's. I was utterly amazed, floored.
"They told her she didn't need to, that they'd use her predicted grades given everything that happened. Nik said, 'Nope!' and took the lot.
"Under the most horrific conditions, after going through (and continuing to go through) it all, she didn't skip a beat.
"It was hands-down the toughest s*** I have ever seen. Sleeves rolled up, get it done. Nothing wasted despite it all.
"She got her results today. Eleven A* grades. I have never been more proud or amazed by anyone.
"In conclusion: my kid sister is the toughest person I have ever met. Don't mess with her. Be inspired!"
PR manager Martyn Hett, 29, was a Coronation Street super fan and stars of the programme were among the mourners at his funeral in June.
He was one of 22 people who died in the suicide bombing carried out by Salman Abedi as revellers left an Ariana Grande concert on 22 May.
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