In Brazil, they call Thiago Silva 'O Monstro' – the monster.
A son of the Campo Grande favelas and abandoned by his father at the age of five, the veteran defender has overcome numerous set-backs to become one of the 21st century's finest centre-backs.
Now, as Chelsea prepare to face Porto in the quarter-finals of the Champions League on Wednesday, he will return to face a club where, having joined them 17 years ago, his career almost ended before it had even properly begun.
At the age of 19, Thiago left Brazilian second-tier outfit Juventude to join Porto in a deal worth €2.5 million (£2.1m/$3m), though instead of being integrated into the first-team squad, he spent the 2004-05 campaign playing for the Dragoes' 'B' team.
It was during a trip to Thailand with the reserve side that the defender began to feel ill, though he originally believed that he was merely suffering from a cold.
In the days that followed, he agreed a loan move to Dynamo Moscow as he looked to get his first-team career back on track. But after only a handful of training sessions with the Russian outfit, Thiago's symptoms began to worsen, as he struggled to breathe when performing even basic tasks.
He was eventually taken to hospital, where he was told what he was actually suffering from was tuberculosis. Doctors informed him that if he had waited just two more weeks at home rather than seeking medical help, he could have died.
Thiago's condition was stable, but due to him not responding to treatment, he was isolated within a medical facility in Moscow for six months due to the contagious nature of the disease.
It was only after his family rejected the suggestion that he have his lungs operated on that he left to return to Portugal, where he eventually recovered after a further six months of treatment.
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"Thiago spent almost one year in total at the hospital," Belle Silva, the Brazil international's wife, tells Goal in an exclusive interview.
"In the middle of the process, after six months in Moscow, they said we can't do anything and they said they were going to take part of his lungs out.
"He wouldn't be able to keep playing football because he wouldn't have 100 per cent confidence in the strength of his lungs.
"When he and the family understood the gravity of the situation, it had already been six months of him stuck in a hospital room. It was very hard emotionally to accept that his dream would be over with this operation on his lungs.
"Thiago was young and I was 17 at the time, so it was difficult to communicate through translators, especially at that age. The translators often only said what they thought we should know, not the whole story.
"After the first six months, I went to Russia from Brazil to be with Thiago. Ever since then, we haven't left each other's side.
"He got the second diagnosis in Portugal and we had treatment there. We lived for six more months in Portugal while he got cured.
"We still felt it might be difficult for him to play professionally after the disease went. Ivo Wortmann (Thiago's coach at Juventude) had given him a chance before, and he did so again at Fluminense. It restarted his career."
That spell at Fluminense did indeed revive Thiago's career and, three years later, he once more moved to Europe, this time joining AC Milan, where he developed into one of the game's outstanding defenders.
Transfers to Paris Saint-Germain and now Chelsea have since followed, but the 36-year-old still looks back on the darkest days of his career and considers what might have been.
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"Thank God that I had the strength to overcome it and get well," he said following his arrival at Chelsea in September. "It is difficult to talk about it because it brings back these memories. It seemed the dream would be over.
"I feel very grateful to my family and my wife, who was very supportive and gave me the strength to get over it so that I was able to then chase my dreams.
"Now, I can say today that I am a champion not just in football, but also in life."
One man who witnessed that journey first-hand was former Portugal international Costinha, who was at Porto when Thiago joined the club before he too made the switch to Dynamo Moscow in 2005.
Though they never played together, the midfielder was aware of his team-mate's condition, and was, thus, amazed to witness the transformation in Thiago when they faced off against one another a few years later in Serie A when Costinha was with Atalanta.
"Imagine someone comes to you and says you can't play football anymore because you have an anomaly in the body?" Costinha says to Goal. "So, Thiago is not just strong; he is like a rock.
"He went back to Brazil and healed himself and he became stronger. He dreamed of playing for Brazil and reaching the top level. He never gave up.
"He has a very positive attitude; he is always laughing and has a good mentality. He is a captain who unites people, not a shouter unless he really has to.
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"I am happy that God helped him overcome that illness. I think it changed him. I think he is stronger now. Maybe he had doubts when he came to Europe from Brazil. After recovering from that illness, he is as hard as a rock because he beat something that’s very difficult to beat.
"If he had had that surgery in Russia, maybe we wouldn’t be speaking about Thiago now and the fantastic career that he is having. He was always a great person at Porto, but he is even stronger now."
That strength and self-believe remain evident in Thiago's game, so it is no surprise that he is optimistic about his chances of representing his country at the 2022 World Cup in Qatar even though he will be 38 by that time the tournament rolls around.
If he is to make the Brazil squad, he will likely need to remain playing at the highest level and the good news on that front is that Chelsea are expected to activate the clause in Thiago's contract that would see him remain at Stamford Bridge for another season.
Thiago would be only too happy to stay, given he, Belle and their two sons are enjoying life in London.
"We are all blue at home, and the kids are happy to be training at Chelsea," says Belle, who has become something of a social media celebrity among Chelsea fans due to her support of the team.
"Thiago is loving being at Chelsea. He thought he missed the chance to play in the Premier League at his age, but it is all down to the good work in training he has been doing to keep fit.
"Chelsea were already in his thoughts; he always respected and admired them and they play in the league that he likes. He likes the staff and all the players, and he is enjoying his time here."
