playing lol with a macbook air

Your MacBook is getting hotter because the components inside are creating more heat because more is being demanded of them to play league of legends and whatever else you have going on. You won't be able to play league and it not "run hot" it's integrated graphics and also an older chip. League is also a very easy game to run so your integrated graphics shouldnt have a problem running the game, but its gonna get hot no matter what because of its a laptop and there's probably not adequate cooling since its a laptop.