Demonic Leap allows a Demonology Warlock to leap forward a fair distance in the direction he's facing.
Using it as you would a normal walljump is pretty much a guaranteed success on any walljump-friendly wall, even after the nerf.
The real benefit comes from the double jump, which is performed by jumping normally straight up in the air, hitting Demonic Leap when you are just about to touch ground, and then again at the apex of the Demonic leap jump. So its spacebar, leap, leap. This will cover a great distance both vertically and horisontally.
*NOTE* I didnt invent this, it has been posted on this very forum by 1lolol7, who I believe was first to describe it. *NOTE*
This jump, along with Soulstone, pets, passive 50% runspeed buff, passive waterwalking+waterbreathing, eye of kilrogg which has unlimited fast slowfall, can scout ahead safely and place remote Demonic Portals, which in turn means infinite do-overs if you fail a jump or take a wrong turn, means that Warlocks are by far the best exploration class in the game atm. This thread attempts to demonstrate what Warlocks can do!
*HINT* If you are stuck on the side of a wall, walljump style, you will probably not be able to summon a safe Demonic Circle, meaning you will slide down when you teleport back to it. Test if its safe to remove your old checkpoint circle by jumping straight up (normal spacebar jump), if you land safely where you started then you can summon a circle and teleport back to it without worry. The same principle holds true for doing a double Demonic Leap.
Outside AQ20:
Start to the northwest of the last boss.
Purple = Demonic Leap
Green = Eye of Kilrogg jump+Demonic Portal (slowfall+mount probably works too but I dont have that)
White = Walk, run or conga line.
At this point you should see a large ramp, run up it and youre now looking down on vast expanses of sand, where you can frolic to your heart's content.
How I frolic. (white part is unknown)
An oasis in the desert of unknown.
On the road to nowhere.
Text that could theoretically be considered witty but also pertains to the image.
Top of EoTS Mage Tower.
Very straight forward, start inside the tower, aim for the bookcase and leap up the bookcase, then jump ever upwards aiming for the wooden stairs. (the normal concrete-type areas are littered with invisible walls, but I never once failed to jump up to the next level while aiming for the wooden staircases, one jump at a time.)
Bunch of Doodad_GeneralMedChair01-32 throughout the tower.
Good place to hold flag
Warsong Gulch Alliance roof
Jump from the 3 roof and aim towards the corner of the tower, thats sticking out.
Very straight forward. The glowy tower drops down into buggy land, pink square and all. Can fall into disconnect/deathfall.
Scarlet Halls
Go to the Houndmaster, go east into the small room. Jump up onto the water fountain thing thats mounted on the wall and Demo Leap to the east, above the roof. Nothing to see really, theres some white ground to the west and some brown ground north of that.
Scarlet Monastery
Go to the last boss, go west into the westernmost little room with a coffin and two candle-holder-things. Jump up from the coffin onto the westernmost candle, and then Demo Leap to the west. Again, really nothing to see as far as I have been able to find, there's a hole in the ground where the instance portal is, but you cant fall down and get on the wrong side of the portal in any way that I could find as the ground is non-solid.
Blackwing Descent
Stand here, below Magmaw (just jump through him and Soulstone when youre below, if you died.)
Demonic Leap and this:
(might be hard to see, its basically white ground with a huge bowl-shaped hole in the middle, Nefarians platform and the elevator are visible, as is Magmaw from certain angles. You can also get a glimpse of some lava if you turn the camera to look down on your character in certain areas.)
(will update this thread with any new explores I find using leap)