Mage Arena is a miniquest which will allow you to get a god capes and staffs after completing it. (Saradomin/Zamorak/Guthix)

How to get there:

Type ::mb in the chatbox, or talk to the Wizard at home, Wilderness - Mage Arena

Talk to Kolodion and select Mage Arena 1

Fighting Kolodion:

While fighting Kolodion, he will switch forms four times after kill you him.

Bring your best in slot magic spell and gear, some prayer potions, and some food incase you run out of prayer. (for example I needed 2 doses of prayer potion with 70 magic)

First form:

Second form:

Third form:

Fourth form:

Fifth, final form :

After killing him 5 times, you may view his shop: