Phase 1 consists of three cycles of attacking Stallord's spine with the Spinner.
On the first cycle, run just past the lip of the arena and then get on the Spinner to head straight to Stallord without latching onto the spinner rail, which is slower. Head straight to the spine and press A to attack. No staltroops will spawn to defend the spine.
On the second cycle, hesitate after the cutscene ends until the camera pans behind Link, then launch off of the spinner rail slightly right to avoid Stallord's arm. Dodge staltroops and attack the spine. With bad staltroop spawn RNG, it can be impossible to make it to the spine immediately; in this case, return to the spinner rail and try again.
On the third cycle, repeat the launch from cycle 2. This time, five staltroops are nearly guaranteed (see notes below) to spawn between Link and the spine as he approaches, so curve to the right of the spine, bounce off of a staltroop, and attack the spine from the opposite side. A staltroop regularly spawns very close to and behind the spine, and bouncing off of this staltroop is fastest.
Note that it is possible to launch off of the spinner rail immediately to start cycles 2 and 3, but the camera being turned makes it very difficult to dodge staltroops that spawn in random locations. It is also possible to start cycles 2 and 3 in the sand if Link gets stuck on Stallord's arms during the cutscene of the spine breaking; if this happens, roll to the spinner rail after the cutscene ends. Finally, it is also possible for the wall of five staltroops to simply not spawn on cycle 3 and allow immediate access to the spine, but it is not known what causes this to happen, and it is rare.
During Phase 2, it is possible to time getting onto the rail to allow Link to catch up to Stallord and knock it down without going all the way to the top of the rail.
To do this from the beginning of Phase 2, roll 5 times hugging the wall, adjusting the camera towards the center of the room to allow Stallord to enter the view. After the 5th roll, continue running for a short time, then get on the Spinner. If timed correctly, Link will be side by side with Stallord. Press A to jump and knock Stallord down.
It is possible to time getting on the Spinner with an audio cue or a visual cue.
Doing an Extended Brakeslide towards the spinner track won't cause Stallord to move forwards, allowing the player to get on the spinner rail directly next to the boss, hitting it immediately. This is the fastest backup method, mainly used as a backup after failing the 5-roll method above, though it is not commonly seen due to its difficulty.
This is the easiest way to retry the fast knockdown on Stallord.
Align Link's face with the first black dot on the wall where his head is above the spinner rail.
Turn left and wait until just after Stallord has shot a fireball.
Get on the Spinner and knock the boss down.
Here is a less commonly used initial setup for the fast knockdown.
It is possible to 1-cycle Stallord during Phase 2 by chaining spin attacks together. The spin attacks must all fit within a moderately tight time window, but it is possible to accidentally slash multiple times and still successfully 1-cycle.
It is possible to 1-cycle Stallord during Phase 2 by doing a precise combination of attacks. After knocking it down, jump attack and quick spin, then do 3 slashes: left, right, forward (stab). Repeat twice more.
Original video by Temchee: here
This is more lenient than the 3-stab strat which did this.
There are several ways to perform the 1-cycle on GCN and occasionally the question of which method is the fastest or "best" pops up. Sva made a comparison video to help answer this question.
[Videos coming soon]
The first step in skipping Stallord is using Clawshot Actor Displacement (CAD) to move a staltroop from the sand to the corner of the exit gate and the wall. This is extremely precise.
(Skip this step if using the clawshot angle setup in step 3) Perform a buffered angle setup.
Ride the spinner just to the left of Stallord's spine and then towards the right side of the exit gate. This will spawn the staltroop needed for the trick and cause Stallord to turn counterclockwise so that he doesn't crush the staltroop.
(Skip this step if using the buffered angle setup in step 1) Walk into the corner of the exit gate and the wall. Enter first person with the clawshot and set up an initial angle using the right tip of the clawshot as a visual cue (see video). This initial angle is precise but not unit-precise, as the remainder of the setup will snap to the correct angle from a range of initial angles.
Turn Link around 4 times by tapping slightly up and down on the control stick. Target, then turn him around once more. His horizontal angle should now be 60562. Unfortunately, it is not easy to tell whether he has the correct angle without practice tools.
Press L to target and continue holding L through this entire step. Backflip into the corner, pressing B to pull out the sword during the backflip. Jump attack twice, waiting for Link to fully finish his jump attack animations before proceeding. Finally, press B repeatedly for a full, 4-part sword combo. During the combo, the control stick should be neutral during the first 3 slashes and down for the final slash. During the final slash, the control stick must reach the down notch at some point. ESS-Down will make the slash look like a down-slash, but it will not yield the correct position. Wait for the sword combo animation to fully finish before proceeding.
Enter first person and aim the clawshot down to the very bottom of the targetable range of the staltroop. Do not aim the clawshot left or right at all. There is a range of about 14 vertical angle units (5103-5090) starting from the very bottom of the targetable range that will allow the CAD to work consistently.
If needed, wait until a spinner passes on the rail so that the CAD will not be interrupted.
Release the clawshot button and begin an up-left notch L-slide 6-9 frames after releasing the button. The L-slide begins when the L button has a full analog press, so the order of operations is to release the clawshot button, move the control stick to the up-left notch anytime before pressing L (or on the same frame), and then press L within the window of 6-9 frames after having released the clawshot. Since the item wheel cannot be pulled and the game cannot be paused while aiming an item in first person, it is not possible to buffer these inputs in any useful way.
The L-slide will move Link towards the ledge of the spinner track, where he will then fall. At any point between initiating the L-slide and Link beginning to fall, move the control stick to the down-left notch while continuing to hold L. It is possible to use the item wheel to buffer this control stick shift to make it easier to find the notch in time.
If everything has been done as described above, then Link will fall off of the ledge as the staltroop arrives, and they will slide together into the corner in which the angle setup in steps 2 & 3 was performed. Roll to escape being pinned in the corner by the staltroop and continue to the next step of Stallord Skip.
Because the setup for the CAD is so precise and it's often not possible to tell whether it has been performed correctly until after attempting the CAD, debugging issues can be difficult. These are some generalizations for troubleshooting common issues:
If the clawshot does not reach the staltroop before Link falls, then the L-slide began on frames 1-4 after shooting the clawshot (frames 6-9 work).
If the clawshot clanks on the staltroop but does not pull it before Link falls, then the L-slide began on frame 5 after shooting the clawshot (frames 6-9 work).
If the clawshot pulls the staltroop when Link falls but stops when it reaches the ledge, then the L-slide began on frame 10+ (frames 6-9 work).
If the CAD pulls the staltroop around the room wildly, then the some combination of the position setup, horizontal angle, and/or vertical angle was wrong. This is the hardest fail case to troubleshoot, so it is recommended to check for the correct angles and position using the tpgz data viewer when beginning to practice the CAD.
If the CAD pulls the staltroop slightly too far left or right instead of into the corner, then the issue may be the control stick notch values used for the first L-slide and CAD. Generally speaking, notch values close to +/-40 work best, while values ~3+ units off can cause this issue. If the controller notches are far from +/-40, then steps 7 & 8 may need to be performed with the control stick slightly out of the notch, with a different controller, or with notch calibration.
Now that the staltroop is in the desired spot, it is possible to use it to clip into the wall.
If needed, throw the boomerang at Stallord's head to stop its flame attack or prevent it from starting.
Position Link as shown in the video. When Link's right foot is forward while targeting, look for the back of the right foot barely hanging off of the small ledge on the black line.
Enter first person with the clawshot. Aim such that the left side of the screen aligns with the left side of the left bar in the gate that only extends halfway down the gate (see video). If the yellow aiming triangles are not present with this angle, then Link's position is incorrect, though this does not necessarily mean that the next step will fail.
Release the clawshot and begin a rightward L-slide as soon as possible. If done correctly, Link will be inside the wall to the right of the staltroop once he reaches it with the clawshot.
The final step of Stallord skip requires bomb boosting within a 3-frame window while Link is clawshotting towards the staltroop. The 3-frame window to press the clawshot button is 152-154 frames after pressing the bomb button to pull the bomb if there is no pause screen, item wheel, or map buffering in between the inputs.
If needed, throw the boomerang at Stallord's head to stop its flame attack or prevent it from starting. See step 1 of the Wall Clip for more information on Stallord's attack.
Position Link against the exterior wall and as far right as shown in the video. This positioning is somewhat precise. For the remainder of the trick, do not aim up or down while in first person, as this will cause the camera to push Link away from the wall exterior wall.
If needed, turn around and throw the boomerang at Stallord's head. Be careful - if the boomerang returns to Link while in first person and the boomerang is no longer equipped to X or Y, the camera will return to third person.
Enter first person and aim the camera as shown in the video, aligning the center of the first heart on the HUD with the line on the wall.
Hold L and press the bomb button to throw a bomb in place. See notes below regarding timing.
Enter first person and aim the camera as shown in the video, aligning the right side of the first heart on the HUD with the line between the dark and light areas on the wall.
If everything has been done correctly, then there is a 3-frame window to input the clawshot button, latch onto the staltroop, and cause the bomb to boost Link out of bounds beyond the exit gate. Press the clawshot button within this window, boost out of bounds, and roll to the load zone to finish Stallord Skip.
This 3-frame window is around the peak of the bomb's 7th red flash. It is possible to buffer with the item wheel to help find these frames, but some may find it easier to time the clawshot input without buffering, even with a visual cue.
Since the clawshot frame window depends only on the bomb timer, it is possible to use a metronome to time the clawshot input. With a tempo of 152bpm, pressing the bomb button on beat 1 and the clawshot button on beat 14 will time the boost correctly. Note that pausing the game in any way (start, d-pad, or Z) between the two inputs will pause the bomb timer and render the metronome useless, so do not buffer or equip at this point if using this method.
If you're practicing on TPGZ or with cheats active, check that the Invincibility cheat is off, as it will prevent the bomb from hitting Link
If the clawshot doesn't connect with the staltroop, then the camera was aimed too far right.
If the bomb kills the staltroop and knocks Link backwards in bounds, then the clawshot input was too early.
If the bomb kills the staltroop but does not hit Link, then the clawshot input was too late by 1 or 7+ frames.
If the bomb neither kills the staltroop nor knocks Link back when it explodes, then the clawshot input was late by 2-6 frames.