Yulian, born in 2011, stands 1.94 metres tall, has represented Spain at under-15 level nine times, and is described by those who have worked with him as a physically dominant, quick-thinking defender whose development trajectory closely mirrors that of his older brother.
According to AS, Real Madrid's La Fábrica academy has been tracking him for some time — a detail first reported by ESPN — and scouts from other European clubs have also taken note.
Valencia are working to extend Yulian's contract and retain him at Paterna. Those within the club are reported to be confident of reaching an agreement.
The situation is described as positive from the player's side — the Mosquera family's relationship with Valencia remains warm despite Cristhian's departure to Arsenal last summer for around €15 million.
That move was completed without friction, and both parties have been careful to ensure it does not complicate Yulian's situation at the club. Real Madrid's interest is known but the club have made clear they do not want to create conflict between institutions.
The family dynamic adds an unusual layer of colour to the story. When Cristhian signed for Arsenal, manager Mikel Arteta photographed Yulian holding a mock Arsenal contract — a moment that went viral in Spanish football circles and underlined the affection Arteta has developed for the older brother during his first season in north London.
Yulian himself has spoken publicly about his admiration for Cristhian and the ambition the two brothers share.
"He is my reference. He gives me advice every day. We have always talked about being like the Williams brothers and reaching professional football together. That would be a complete dream."
Whether that dream is eventually fulfilled at Valencia, Real Madrid, or elsewhere will depend largely on the contract talks now underway in Paterna. For now, the club hold the initiative — but Madrid are watching closely.