Instructions
Open your World Map and choose to attack "The Hollows."
Give your Barbarian Chieftain Waders and send him to capture the Tower, while ignoring the Portal in the middle.
Use the Recruitment Orb to summon a Werewolf and a pair of Barbarians.
Send the Werewolf to protect your Barbarian Chieftain, while sending your Barbarians to capture the villages on the left and right side of the Tower.
Continue capturing villages with your Barbarians.
Use the Recruitment Orb to summon more Werewolves and Rangers and send them to help capture the Tower.
Capture the Portal in the middle once the Tower is secure.
While capturing the Portal, continue capturing villages with your Barbarians. If done quickly, you can take six villages without having to battle for them.
Continue producing Rangers and Werewolves and sending them to the middle Portal. By now the boss character Saradomin and his army will have arrived through the middle Portal. Throw everything you have at them, while sending your Barbarian Chieftain to capture the Portal. Once the Portal is captured and Saradomin goes down, you will have unlocked the Dark Knight.