The 19-year-old Ivory Coast international has emerged as one of the brightest young talents in Europe after a breakthrough campaign in Germany, carrying that form onto the World Cup stage where he has become a key figure for the Elephants.

On Saturday, Diomande is set for a special occasion when Ivory Coast take on Germany in Toronto, a match that pits him against the country where he has flourished since joining RB Leipzig.

Yet as his stock continues to rise amid reported interest from several European giants, including Liverpool and Paris Saint-Germain, Diomande revealed that much of his motivation comes from the memory of his younger sister Roxane, who died last year at the age of 15.

In an emotional letter published by The Players' Tribune, Diomande described the devastating moment he learned of her death shortly after making his professional debut for Spanish side Leganes against Real Madrid.

"What are you talking about?" he recalled asking after receiving the phone call from Ivory Coast.

"Somebody put something in her drink at a party, and she never woke up. She is gone."

The teenager admitted the news left him numb.

"I don't even think I shed a tear the day they told me that you were gone. I was just in shock," he wrote.

"Since you died, I'm just blank."

Diomande said he continues to wrestle with unanswered questions surrounding the tragedy and whether he could have done more to protect his sister.

"I never got any answers. I don't know if I want to know why. Maybe it was jealousy. Maybe it's just something that happens in our country. Maybe I could have protected you. I don't know," said the talented forward.

The winger, who left Ivorian as a teenager to attend a sports high school in Florida, endured a difficult path before reaching the elite level. Unsuccessful trials with MLS clubs Charlotte FC and Colorado Rapids were followed by further opportunities at clubs including Chelsea, Crystal Palace, Bournemouth and Olympiacos before Leganes eventually offered him a professional contract in late 2024.

His progress since then has been remarkable. After impressing in Spain, Leipzig moved quickly to secure his services, with sporting director Marcel Schaefer revealing that the club identified his potential long before he became a household name.

The move has paid off spectacularly. Diomande scored 12 goals and contributed eight assists in his first Bundesliga season, performances that have reportedly attracted attention from some of Europe's biggest clubs.

Despite speculation over a possible transfer and reports suggesting he could command a fee approaching 100 million euros, Diomande insists he remains focused on gradual improvement.

"I'm not the person who likes to be in the future so quickly," he said earlier this year.

"I'm going step by step because I have a new dream every day. I want to be one of the best. But I want to go slowly, slowly, step by step."

For now, his attention remains firmly on the World Cup and on fulfilling the dreams he once shared with his sister.

"I try to trust God's plan. It's all I can do," Diomande wrote.

"All I can do is use the pain to work harder, and to do everything we dreamed about.

"I will make sure that everybody knows your name. The whole world.

"Everything I do on a football pitch, it's for you."

Leverkusen fully focused on upcoming Supercup clash with Stuttgart