Want to know whether Demon Mobs, Demon Slayer, and the relocated Random eventers are worth bothering with? Then look no further.
Demon mobs are a sort of combat 'evil tree': remote, but this time announced within the game window. You need to have the right combat level, but they're good fun: however, if you are planning a session of hunting, it makes much more sense to join a friends chat like SaintProdigy (I might have got the name slightly wrong, if I have google it): while you don't lose any of the rewards for doing so, you can still find mobs a lot faster.
If you want to do this effectively, you've got two options: risk a lot more by running around the wilderness (but the potential gains are higher) or go around the standard world. Most of the locations can easily be reached by lodestone, while fairy rings will take you to the Feldip and Uzer areas, and a charter ship can take you to the Poison Waste. The trick to doing well is to constantly hunt and to be communicative with your fellow hunters.
A standard 5 minute hunt works like this: you get a call out, such as 'w6 uzer spawn'. Replying 'omw w6' (on my way), you hop worlds and then lodestone to Edgeville, before taking a fairy ring to Uzer's ruins. You then run north, hoping you brought some water, and find the demon mob and lots of other players. A full battle involves 4 stages: first, you kill the imp heralds, then the lesser demons, then the lieutenant demons, then the general. The general will be different (in attacks) each time, but it doesn't really matter, and each tier is frozen in place until the previous one dies. It's a bit strange, because they're not aggressive or anything, but it's hard to see how Jagex could make them more threatening to the world without simply inconveniencing players who would world-hop out the way. As long as you get a hit above 500 on the general (you'll be notified when you do), then he'll drop some loot for you: this is why nobody misses out if they arrive with a group instead of alone. The loot is generally worth roughly 25-100k per kill, but if you get a piece of demon hunter equipment, that's worth significantly more, not on the grand exchange but worth a few million in street price. Depending on how quickly you can make the kills, you should make a perfectly reasonable amount of money, even if it's not a perfect money maker-those tend to be a lot less fun.
All in all, an excellent DnD and a fine way to make a little cash without any real preparation if you want to do so with combat.
Demon Slayer is a quest that's been around for a while: it preceded the slayer skill but nicely fits the tone of it, as you have to find a special sword. I'm reviewing it because it was recently revamped and is now a rather different quest. In summary, you meet a demon hunter in the Varrock Church, you go below the church and perform 3 quick/easy puzzle/challenges, you get the sword, and then you go under the Zamorakian Temple, kill some cultists (all enemies except Delrith are level 2), and then fight Delrith, a level 15 demon who periodically uses an AOE attack that you have to stop fighting and stand next to the demon hunter to avoid.
While I'm all in favour of revamping ancient quests, I don't think this was particularly well done. It was never quite explained why the demon hunter couldn't go and fetch silverlight himself: indeed, it was explained that this was his ancient right. The quest removed Wally, an established piece of lore that could easily have been kept, and also removed Gypsy Aris, a great character that wouldn't have been hard to fit in. The crypts under the churches are massive, purpose built areas that don't really fit into a wider context of what's below Varrock and why the sword is there, while the previous version (unlocking it from Sir Prysin) certainly made more sense to me. Sir Prysin is a nobleman, you are a warrior, it seems a fairly simple transaction. Finally, Delrith is strange: you fight him way below Varrock in a seemingly purpose-built arena, utterly disregarding the stone circle for no clear reason. He also fails to be powerful yet again. Given that silverlight is made to kill demons, functioning as a rune longsword against them, and is specifically made to kill this demon, why not have a mechanic whereby it counts as an even more powerful weapon, or explain that Delrith is only weak because he is freshly summoned, as happened previously.
If I was to revamp the quest, I would have kept the key mechanic and the idea that Silverlight has been treasured as a holy artefact. I would also have made the crypts, a nice idea, a bit more sensible, with smaller size but no less significance. Finally, I would have either removed the stone circle (perhaps putting it below the temple?) or had Delrith summoned there.
The quests did some things right, but it went for an over the top epic feel that disregarded plot and established lore in favour of pretty dungeons. As such, it was ultimately jarring, and I don't think it was as good as it could have been.
On a more positive note, the Relocated Random Events have been superbly done and are really worth checking out. If you've got time for nothing else, I recommend visiting Mr Mordaut and the Mysterious Old Man, to characters who became increasingly important as the game aged because of their role in the 'postbag from jagex', something that seems to have stopped now. Probably because players don't write letters.
Anyway, Mr Mordaut has an excellent office in the basement of the Varrock museum: go down the stairs, and enter the door on the stairway that bears one of the symbols there used to be in his schoolroom. He's all up for an interesting conversation, and particularly serves to give some new plot exposition on the dragonkin: I won't spoil anything, but he's well worth a visit if you've completed any relevant quests.
The Mysterious Old Man now owns the house in Draynor opposite Morgan's. He's fairly chatty, if just a little bit creepy, and also provides some interesting dialogue. Of real note here is that if you can get him to go away, you can go into his basement, which contains a variety of different random events items in a sort of workshop.
Various other previous events also exist. Leo the gravedigger, for example, has a spot in East Ardougne's church, and others can be found by talking to the mysterious old man.
Overall, this was spectacularly well done. Old characters have new and memorable dialogue, but it's done in a careful way that makes them fit into the world they are part of and seem like they could have always been there. If you're looking for a chat with some of them, the mysterious old man has all the info you need.