Jhen Mohran GS Speedrun

Monster Hunter Portable 3rd - Guild | ★8-39 | Jhen Mohran | Great Sword | 09'07"80
https://www.youtube.com/watch?v=9olX-pU8Jeg

Despite being the Monster Hunter-equivalent of an autoscroller, there are many small, interesting ways to make this hunt progress faster.

First off, the rare skill, Fortify, is used for this hunt.  The first time you fall in a hunt, your attack power goes up by 10%.  The second time you fall, that increase becomes 20%.  Because of the automatic nature of this hunt, there's plenty of time to set up Fortify and Heroics without losing any time for a grand total of 62% extra attack power.

Secondly, there is a timer that counts down between every action the Jhen Mohran performs, and it does not count down during the actions themselves.  The Jhen Mohran's stagger animation is shorter than most of its attack animations, so if it is staggered at the very beginning of its attack animations, the timer will resume sooner and continue onward.  The only attack that is shorter is the rock throw, so I just let it go.

Lastly, the spine stagger.  Throughout this hunt, I do damage to the spine (not the cracks) to build up the spine stagger.  This is to set up a "stagger" of sorts for the final showdown.  I'll explain this more in the walkthrough.

0:11 - Setting up Fortify and Heroics.  I use a combination of bombs, bitterbugs and the Jhen's rocks to set up.
2:10 - I use the hunting gong to stagger the Jhen out of the first ram.
2:31 - I jump on the Jhen's back and place an anti-dragon bomb on its spine.  This is not only to do some damage to the spine but also sets up the timing for the attacks and subsequent stagger on the spine crack.  It's important to note that the second ram will hit you if you're on the side of its spine nearest to the ship and not the far side.
2:53 - Using precise timing, I stagger the Jhen out of its third ram.  I build up stagger on the rear spine crack.
3:08 - Before the rock throw, I make my way to the near side of the spine.  I do this because I need to let the rock throw animation play out as well as be in a position where I can jump off.
3:15 - I precisely stagger the Jhen out of its tail attack.  With the rear spine crack broken, I move on to the front and immediately start building up stagger.
3:43 - I tap it with a normal swing to stagger the Jhen out of the preliminary shaking before its final buck.  I quickly drop my second anti-dragon bomb near its spine and jump off.

During this downtime, I'll explain the Jhen Mohran's HP.  Every Jhen in this quest has 19,240 HP.  In the first phase, its HP will cap at 20%, which is 3,848 HP.  Getting its HP down to this point will force the hunt into the final showdown at the next opportunity.  This is the major goal of the first phase and so I dish out as much damage as I can.  This seems like an obvious strategy, and, yes, it is.  However, there is one nuance regarding hitzone detection that lets us reach that 20% cap in record time.

When the spine cracks are broken, you supposedly cannot hit them anymore.  However, due to a discrepancy with hitzones, it is still possible to hit these spine crack hitzones even after they are broken.  Each broken spine crack has a different sweetspot that can be hit with precise aim.  This will allow us to deal more damage than intended and hit the 20% HP cap at the end of the upcoming phase.

5:13 - The Jhen rams the ship head-on.  This is one of two possible attacks it could do at this time.  The other is a body slam on the ship, which is slower.  An amusing note is that this is the only true variance in this entire hunt, aside from the Delex.
5:28 - I use the hunting gong to stagger the Jhen out of its tusk sweep.
5:46 - I jump on the Jhen's back once again to finish off the front spine crack.  After two hits, I let the rock throw happen and then, with precise timing, go back to work on the spine crack and break it, staggering it out of its next attack.  I take this time to do some more damage to the spine.
6:30 - This is where the fun begins.  Again, using precise timing, I start hitting the very top of the inside of the front spine crack's hole.  For whatever reason, this counts as hitting the spine crack, dealing a ton of damage and building up the crack's stagger.
6:51 - I had some extra time, so I dealt more damage to the spine.  This sets the spine stagger up perfectly for the final showdown.
6:57 - I deliver the final blow to the front spine crack, staggering the Jhen out of its attack.  I move on to the rear spine crack.  The sweetspot for this crack is somewhere between two segments of the spine near the crack.  After staggering the rear spine crack twice, the Jhen is down to our goal of 3,848 HP, and with perfect timing, as the Jhen reaches the end of its phase and descends.

Remember that spine damage I was doing during the first phase?  Besides just damage, it was a very important setup for a stagger in the final showdown.  Although, we will be attacking its belly and it actually isn't a stagger at all.  For whatever reason, dealing damage to the belly counts towards the spine stagger during the final showdown.  And for whatever other reason, this "stagger" only works after the start of the Jhen Mohran's roar animation onward and all it does is force a rock throw.  Don't ask me why.

8:30 - I have time before the Jhen Mohran passes the invisible wall, so I refresh a might seed and use dash juice to cut down on time it takes me to reach the monster, as well as solving my diminishing stamina.
8:54 - I get to the Jhen just in time to start attacking its belly, dealing damage and building up that spine stagger.  I use a visual cue for this to set up the stagger just as its roar animation starts.
9:01 - With this hit, I reach the stagger threshold for the spine and the rock throw animation cancels the roar animation.  Being very careful, I continue my assault on the Mohran, eventually hitting the stagger threshold a second time, which knocks it over.  I hit the monster with one last fully-charged slash, and with little HP left, a quick slap finishes the job.

Drink Skills:  Attack Up (L), Felyne Sharpshooter, Felyne Heroics
Armor Skills:  Attack Up (M), Quick Sheath, Fortify, Focus, Critical Draw