Tencent owns 40% of Epic Games, 100% of Riot, and I think 10-15% of Bluehole. As well as 85% of Supercell, 80% of Path of Exile, 5% of Ubisoft, 5-10% of Activision (Blizzard), and notable shares in a variety of smaller studios that publish Cities: Skylines, Crusader Kings, Lineage 2, etc. They also fully manage the publication of games like Candy Crush and PUBG in China and even developed PUBG Mobile.
Tencent basically originated as an instant messenger with gaming integration so it's no surprise that they have large stakes in the gaming industry. It also helps that they're a huge company that dwarfs every gaming company in existence.