We're exaggerating of course. There are only three Hazard brothers currently playing professional football and many more countries in Europe. But with Eden in England, Thorgan in Germany, and Kylian in Hungary, the Hazard brothers' rivalry does span a good portion of Central and Western Europe. The fourth brother, Ethan is only 12, so he's exempt for now.
It's a friendly rivalry, as brothers are wont to do, involving goals, assists, and family meal. Loser buys.
"We have a competition every year also with my other brother who plays in Hungary [Kylian]. I need to score and give assists because I don't want to pay. For the moment it's a big competition between us."
-Thorgan Hazard; source: The Set Pieces
The interview does not reveal the specific rules for scoring the competition, though it's agreed that Eden still leads despite his vastly subpar year. England's reigning Player of the Year has 2 goals and 8 assists in all competitions. Meanwhile, Kyllian has been doing well at Újpest, who are second behind runaway leaders Ferencváros. Thorgan has played the least of the three brothers, but he's not far behind at all and has recently started seeing more regular action for Borussia Mönchengladbach.
Maybe Thorgan should advocate that they change the rules to a per-minute basis.