"I’d personally stopped him strangling two referees. However, I had no suspicion about what he was planning to do...."
-- Ivan Popa's testimony to the Enquiry following the disaster (Pm)
With Romania losing, Nenad set off the forest in a rampaging attack known to history as the “Attack of the Killer Forest“. Popa saved the day, later testifying that Nenad had been acting strangely for some time. He won International Wizarding Order of Merit for his efforts to save lives during the seven-hour battle with the trees (Pm).
Ivan is a form of John, deriving from the old Slavic name Іѡаннъ (Ioannu) and Hebrew יוֹחָנָן (Yochanan), meaning "Yahweh is gracious" (Behind the Name).
Popa is a common Romanian surname meaning "priest" or "pious person" (Ancestry).
From the Web
Writing by J.K. Rowling on Pottermore: History of the Quidditch World Cup
Screenshots of the original Daily Prophet coverage of the 2014 Quidditch World Cup on Pottermore: Imgur archive