This guide has been created to display the boss fight that is required to unlock the mage arena II capes - as an alternative method rather than buying the capes from the vote shop.
You can start this by talking to Koloidon who's found in mage bank.
To start Mage Arena II, you should have completed Mage Arena I minigame first - A guide for Mage Arena I can be found below (click on "Show" for the spoiler).
Spoiler for :
Setup
If you are starting out, you could use the following setup - which has been tested and works (just takes 3-4 extra minutes rather than best in slot gear)
The setup can be changed
Make sure to bring all 3 god staves, as well as a rune pouch filled with Blood, Fire, and Air Runes.
With the runes - you'd be able to use the spells in the picture below as well as the "Charge" spell to increase the power of the spells when wearing a mage arena cape!
Flames of Zamorak - against Porazdir | Saradomin Strike - against Justiciar Zachariah | Claws of Guthix - against Derwen
USE THE CHARGE SPELL BEFORE THE FIGHT STARTS
WARNING: This fight is in wildy + Instanced and there won't be a gravestone in case you die - So don't risk extra items in the rare case of dying during this mini-quest because you can't get them back.
First Wave
The first boss you got to kill is the Zamorak boss "Porazdir" so you'd need to use Flames of Zamorak spell with the use of a zamorak staff or use Staff of the Dead instead (can auto-cast the spell).
There isn't any special attack during this wave.
Second Wave
In this wave the Saradomin boss will spawn "Justiciar Zachariah" and you'd need to use Saradomin Strike with the use of the Saradomin staff or the alternative weapon that can autocast would be Staff of Light (can auto-cast the spell).
The boss has one special mechanic - which would throw a blue wave towards you - You'd have to move away atleast a tile to avoid it. If the wave hits you, you'd be teleported next to Justiciar Zahariah and also get a 20+ damage hit from it.
Last Wave
The Guthix boss "Derwen" will spawn and you'd need to hit it with Claws of Guthix spell by using a Guthix staff or use Staff of Balance (can auto-cast the spell) as well as Void Knight Mace (can also auto-cast the spell).
The boss can throw out green orbs that will do 30+ damage if you allow them to touch you, and if they are not killed each active orb would heal Derwen 5 hitpoints over time.
For this special attack, you'd need to dodge the orbs whenever they are thrown by Derwen and then focused down so that you can finish the miniquest.
Full Run Demonstration
Rewards
Once you've finished the fight, you'd be done with Mage Arena II miniquest and would be awarded with 1x Imbued Zamorak Cape , 1x Imbued Saradomin Cape and 1x Imbued Guthix Cape .
Hopefully you'd find this guide helpful in completing this miniquest!
Good luck!