Feyzullah Yusein is a legal counsel at "Kostov & Partners", specialising in commercial law. He completed his secondary education in Lisbon, where he grew up, and later continued his academic path in Frankfurt, Germany, studying law at Johann Wolfgang Goethe University. In 2018, he returned to Bulgaria and enrolled in the Faculty of Law at Plovdiv University.

He graduated with distinction and, in 2025, obtained full legal capacity. Mr. Yusein is proficient in six languages – German, English, Portuguese, and Turkish – enabling him to confidently serve both national and international clients of "Kostov & Partners."