Does Khalifa suppose to be Allah made or man made?

Quran: 2:30] Behold, thy Lord said to the angels: "I will create a Khalifa on earth." They said: "Wilt Thou place therein one who will make mischief therein and shed blood?- whilst we do celebrate Thy praises and glorify Thy holy (name)?" He said: "I know what ye know not."