The treasure hunts on Fire Isle have been available since v2.4, so this is actually a very old game feature. There doesn't seem to be any guide on it so far, so here it is.
What Do I Need To Hunt?
There are several things you need to be a treasure hunter. You must:
- Have at least 1 veteran (or above) character in the party, otherwise you cannot open the treasure chest.
- Have at least 1 character capable of using detection skill, i.e. Scout, Angie, Yeganeh (aka Diego), Jack, or Lorch. See Install Trap stance.
- Have Fire Isle Treasure Key (1m vis) in your inventory.
- Have Fire Isle Zone 1-3 Keys in your inventory, if you intend to hunt beyond the Free Zone.
Using detection skill provokes nearby monsters, so make sure your characters can survive getting hit by the mobs in the zones you are hunting. Stopping to heal is a waste of time, so use potions if you really have to heal. Use multiple detection-using characters for maximum effect.
Treasure hunting is about movement speed, so bring along a buffer (e.g. scout). Use movement-enhanced equipment (e.g. armor, boots) if available. If you are feeling rich, you can use Hermes Potions and premium wings as well.
Let's Hunt Treasure!
When the treasure hunt is about to begin, there will be multiple system-wide notices in yellow text on top of the screen. The first one is...
[Notice] Treasure hunt in Fire Isle area will start in 10 min.
When you see this notice, you can start making your way to Fire Isle (channel 1 only). If you miss the first one, it is still okay, because another notice will flash 5 minutes later. Having a warp to Gigante Port helps, but it is not really necessary.
[Notice] Treasure hunt in Fire Isle area will start in 5 min.
Once you reach Fire Isle, set up your characters. Buff acceleration for movement speed, meditation for HP/SP recovery (if necessary), and prompt action for reduced casting time. If you are using multiple "detectors", spread them out to cover a maximum area at the start. In 5 minutes, another notice will flash.
[Notice] Treasure hunt in Fire Isle has started. You can find the treasure chest using the detection skill. Treasure hunt will end in 10 min.
Now, run around the map, and spam detection skills. Try to cover corners. If using multiple detectors, you can run your other characters to the next spot while the current detector is still detecting. You have 10 minutes to hunt the treasure.
When someone finds the treasure, there will be another notice, stating who has found the treasure. So if XYZ family found the treasure, the notice will be:
[Notice] XYZ Family has found the Fire Isle treasures.
Once this happens, a treasure chest with the finder's name will appear near the finder. The chest can only be opened by the finder, so don't bother trying to "steal" someone else's treasure.
The finder can then click on the treasure chest with a veteran (or above) character. The Fire Isle Treasure Key will be consumed, and the chest disappears with a random Lv.100 AR30 generic weapon (e.g. Bracelet of Ziz, The Black Dragon, Grim-Wight) and 2 random Lv.84 elite weapons on the ground. The 3 weapons are tagged, so only the finder can pick them for the first few seconds.
If nobody finds the treasure within 5 minutes, there will be another notice.
[Notice] 5 min before the end of the Fire Isle treasure hunt.
If nobody finds it after another 5 minutes, there will be a final notice.
[Notice] The Fire Isle treasure hunt has ended.
If you are in Zone 1-3 when this happens, you have just wasted your keys. So you might want to stay in the zones for a while to farm some chips to cover the costs of buying keys.
Some common questions and their answers...
Q. Which zone does the treasure chest spawn?
The chest spawns (invisibly) randomly in any of the 4 zones of Fire Isle (channel 1 only).
Q. Which spot does the treasure chest spawn?
It is random, but there are certain spots in which the chest has been known to appear. For screenshots of where the chest has been found by me so far, see the old entries of my family's weekly journal - Ashardalon labeled blog posts.
Q. When will there be a treasure hunt?
There are 3 treasure hunts per week. The exact time is somewhat random.
Q. Is the treasure worth hunting?
This depends on your server's economy. The cost of treasure hunting is in the keys, i.e. about 1m-2.4m vis. The rewards are 1 Lv.100 AR30 weapon and 2 Lv.84 elite weapons. So, consider the current prices of Lv.100 weapons/chips and Lv.84 elite weapons in your server, and decide for yourself if it is worth the trouble. In general, however, the mass drops of Lv.100 weapons in the newer missions (e.g. Team Arena, Arsene Circus, assorted v4.1 raid missions) have lowered the values of these weapons.
Q. Who is commander.CommName?
Sometimes, a bug exists that prevents the family name from being loaded properly into the script. So the displayed family in the "treasure found!" notice becomes ..commander.CommName.. instead. This is not a real family; it is a (bugged) variable for the script to load the finder's family name. Since the bug makes the finder unknown, just look around you as the finder might be you.