Towards the south eastern side of the island, the landscape changes to a more swampy (probably familiar) environment, with rock crabs bordering it on the beach area by the water.
You can also travel to this area using the portal nexus, and selecting 'Training' > 'Barrows'.
Here you'll find perhaps a familiar RSPS experience of barrows brothers on top of the hills, which I personally have a lot of nostalgic feelings around, but also a new chest a little north of the brothers.
Examining Dharok, for example, you'll see that there's an interesting few items in there.
Barrows brothers always drop 'ethereal essence', which is a crafting material used to repair barrows gear, but also repair the more rare 'ethereal' gear that you can see in the 'Ethereal' drop table.
Also, like shown in tutorial island, of course the brothers have a chance to drop a teency weency version of themselves who will fight alongside you in combat.
The ethereal key you can see there is used to unlock the ethereal chest that I mentioned before.
Here is another way for you to get barrows armour and ethereal weapons, with a twist where if you focus on killing one of the brothers a lot, you can still get items/pets for the other brothers via the chest.
A cool twist with the ethereal weapons is that if you match them up with the equivalent set of barrows armour, you don't just get the higher stats from the ethereal weapon, but also varying 'set bonuses' for combining them together with the corresponding armour.
The Ethereal Hunllef
The Ethereal Hunllef is the first world boss I've created which spawns every
n real time minutes since it was last defeated.
When it spawns, there's a broadcast to the entire server and you're able to type a command to teleport directly there and join the fight with all of the other players. There's a slight cost of ethereal essence to enter the room, but nothing too crazy for anyone who's got the gear to be able to fight it in the first place.
The mechanics take a lot of inspiration from The Gauntlet, of course, with a need to switch prayers, dodge the red ground tiles, run away from tornadoes, and avoid standing under the Hunllef. This is sort of a mid-tier boss where you should be able to fight it with around level 80 stats, and barrows gear. In fact, using a full set of barrows against it will provide you with a 20% accuracy and damage buff towards it!
The Ethereal Hunllef will drop the same ethereal weapons you saw that can come from the barrows brothers, but on top of that a higher tier ethereal scimitar and bow (and of course, a combat pet!)