The Faydown Cloak in Silksong is an upgrade to Hornet's cloak that allows her to double jump, and honestly, it's obscene how much this particular Silk Skill makes platforming around Pharloom easier. That said, getting your hands on the ability to double jump in Silksong is no easy feat.
Located in Mount Fay, the Faydown Cloak - and thus, the double-jump ability - lie at the end of one of your toughest platforming challenges in Pharloom yet. Fortunately, the hike to the top of Mount Fay is well worth it once you've got your hands on this useful Silk Skill.
Here's how to get double jump (also known as the Faydown Cloak) in Silksong.
As mentioned, the Faydown Cloak - and thus, the double-jump ability - can be found at the very top of Mount Fay in Silksong. To climb the mountain, you'll need to have unlocked on the Clawline Skill found in the Underworks. Even then, ascending this mountain is far from easy, and platforming isn't the only enemy here; the environment is too.
Mount Fay is cold. So cold that after a certain amount of time exploring the region, Hornet will very quickly begin to take damage if you don't quickly find a source of warmth. There are plenty scattered throughout the area, but you'll need to swiftly platform across perilous areas to reach them in time. On top of that, there are icy lakes to avoid falling into at all costs.
With housekeeping out of the way, here's the route up Mount Fay - to the Faydown Cloak - on the below map:
First things first, make your way to The Slab's Bellway and head left to enter Mount Fay. Use the Clawline discs to continue left, where you'll then arrive at Shakra and a Bench. Purchase the Mount Fay Map from Shakra for 40 Rosaries.
From Shakra, we want to Clawline onto the platform to the left of her, then go up and right using the platforms (pictured below) to exit into another room. Be careful to not fall into the icy water below as Hornet will very quickly take damage from it.
In the following room, you ultimately want to go upwards. You'll need to quickly use Clawline on some enemies to reach the Clawline discs here, and keep a careful eye on nearby walls you can jump to.
A good rule of thumb is that if you can't see a platform, Clawline disc, or enemy to use Clawline on, then you likely need to dash towards a wall and climb further up to reach one.
Once you reach the next source of warmth, head left and upwards, using Clawline to carefully traverse past the spikes. At the end of the spiked passage, there'll be a source of warmth along the wall and another wall on the right you can use Clawline to reach.
From here, you'll need to use Clawline on three enemies to keep ascending. After them, keep left to come to another source of warmth.
Exit into the room on your left. You can sprint through here but be sure to grab the Silk spools along the way, and be careful of the drop at the end.
At the end, you want to drop down - using the Drifter's Cloak to be safe - and exit into a room on your left, but be careful of the enemies along the way. They won't actively attack but after a short delay, these guys will explode and fire spikes at you so steer very clear of them.
In the following room, be cautious. There's a huge Silk spool to grab here but also a Servitor Boran enemy that fires projectiles that deal two Masks of damage. I recommend running past them for now!
Attack the wall at the end of this room to proceed. The following room requires more careful use of the Clawline ability, but it's worth bearing in mind that there are two platforms in here - attached to icicles - that can be attacked. After attacking them or using Clawline on them, they'll fall into the lake below and make traversal of this area that little bit easier in future.
In the following room, which is fortunately warm, you should see a locked trapdoor below you.
Head left, exiting into the outdoors again, and jump down to the bottom right corner of this area. There's a breakable wall here that we can use to reach a Bench (which costs 60 Rosaries to unlock), as well as the trapdoor lever just above it.
Low on Rosaries? Well, try hitting the wall directly to the right of the Bench. There's a small Rosary cache here, and if you continue along this section, you'll also get your hands on the Memory Crystal Tool which I found incredibly useful throughout the rest of Pharloom.
To proceed, head upwards of the Bench and exit this room to the north. There'll immediately be a heat source on the left.
This next section features, you guessed it, more platforming and using Clawline. From the heat source, climb the wall directly to the right and hop onto the platform. You want to use these platforms, the enemies in the area, and Clawline to keep ascending.
There will come a point where you reach a platform and there are no enemies or Clawline discs nearby (pictured below). You want to carefully jump onto the wall in the upper-left here, where there is a heat source.
Keep heading upwards and right, using Cling Grip and Clawline to carefully maneuver the spiked passage. When you come to the wall at the end, you need to carefully drop from this and Clawline onto the enemy on the other side of it (pictured below).
There'll be two enemies to use Clawline on here before arriving at a platform with a heat source. Ignore the enemies above you and keep heading right.
The next room contains a passage coated in spikes that you'll need to carefully glide down. At the bottom, there's a heat source on the left-most wall.
Your goal in this room is to use Clawline on the enemies to keep right and upwards, being careful of the dissolving platforms along the way.
At the very top, you'll need to Clawline from the final enemy onto the left wall, before jumping over to the ledge on the left (where there is, thankfully, a heat source).
Enter the following room where you won't be at all surprised to learn that there is another icy lake with more enemies and more platforms to use Clawline on. After this lake, however, there's a huge spool of Silk to use!
Exit to your right. In the next room, jump over to the ledge on your right, and again, exit to the right, jumping over the Servitor Boran enemy along the way.
In the following room, attack the breakable wall here. This creates a shortcut for if you happen to fall back to the bottom of the mountain.
Once again, you want to use Clawline on the enemies and discs to your right to keep ascending, being mindful of how much Silk you have. From the final disc, Clawline onto the wall to your left and exit to the north.
Immediately head left and attack the wall to reveal another Bench and heat source.
From the Bench, exit the warm room and climb the wall here, allowing you to Clawline onto a disc to the right. You then need to hop onto the wall to your left, Clawline to an enemy on your right, hop on the wall to your left again, and Clawline to a disc on your right again. Finally, Clawline onto the wall on your left... again.
The short of this is that you want to use Clawline to zigzag between walls and discs/enemies while gradually ascending into another spiked passage.
Fortunately, there's a heat source in this spiked passage. From the heat source, Clawline to the right and carefully drift down before quickly Clawlining onto the enemy on your right here.
There'll then be some more dissolving platforms to quickly traverse before heading left and upwards. Run left here, being careful of the gaps between ledges, to reach another heat source along the left wall.
From this heat source, you know the drill; Clawline onto the enemies and dissolving platforms to your right, then onto the left wall. Climb up this wall, taking caution of the spikes, then continue Clawlining your way upwards to the room's exit.
In the following room, head upwards, then Clawline to the left to reach a huge draft you can float up using Drifter's Cloak.
Head to the very top of the draft and Clawline to your right, where you'll finally have reached the altar for unlocking the Faydown Cloak.
Now you'll be able to double jump and also won't take any damage from the cold, so you can freely explore Mount Fay with a little bit more ease. Enjoy!