Dagon'hai Monks are found after finishing the Hunt for Surok miniquest. They can be found by entering the Chaos Tunnels via the entrance near the Mage of Zamorak. Once in, players should run south past the Giant Rock Crabs and use the southernmost portal. They sometimes drop their robes which are used during While Guthix Sleeps. Players do not need to have started this quest to get the robes as a drop, but to wear them they need 40 Magic, 40 Defence and to have completed the miniquest.
Dagon'hai monks are aggressive and attack using the spell Earth Bolt. They are located in an area with Zamorak warriors which are also aggressive. It is possible to avoid fighting the Zamorak warriors in certain places. However, they will still attack occasionally, so it is best to bring some food as the warriors can consistently hit in the 80s.
However, after around 20 minutes of combat around the cavern, they lose their aggressiveness against you.
Before Monday, 13 October 2014, Dagon'hai monks were often used by low to mid level players seeking to gain fast experience per hour in Attack, Strength, Defence, Magic, and Ranged. Rates of 60,000 to 90,000 experience per hour were achievable at only level 50+ in each skill. For comparison, bandits pre-Evolution of Combat granted 50,000 to 60,000 experience per hour at 90+ in each skill.
As of the Ironman update on Monday, 13 October 2014, Dagon'hai monks have been updated to reflect the changes made in the Evolution of Combat update. They now deal damage proportionate to their level, and have a normal amount of health, making it pointless to train combat on them.