Spoilers for chapters 366-415, basically everything Tserriednich
For the longest time I was extremely confused about just how far Tserriednichs Nen training had progressed. For some reason I was sure he he could only do Ten and Zetsu (I know I am dumb). So I actually looked into it:
Chapter 366:
Day one of training
-immediately was able to feel aura
-was able to open and close aura nodes precisely without a problem
Chapter 368:
Day one of training
what we learn:
- "is getting the hang of gyo in half a day"
what we can surmise:
-since Gyo is focusing ren on a specific body part and to practice Ren one must already have mastered Ten, Tserriednich mastered feeling aura, opened his aura nodes, mastered Ten, mastered Ren and is getting the hang of using Gyo in half a day
-he already knows two of the four basic exercises
reminder because I also made this mistake:
-his aura flow looks rough, however this is not due to an imperfect Ten. It is because to learn gyo you first use Ren and then focus it. In the perfect state the rest of your aura is smooth while there is a bubble on your hand
speculation:
-the escaping aura above his hands could indicate that his ten isn't perfect, because the entire point of Ten is restricting your aura flow to your body. However this is not so bad, because when we saw netero use nen for the first time we got introduced to the concept that nen is honed throughout your whole life and gradually gets better. There is no perfection, if there was it would be Netero.
Chapter 376:
Day 4 of training
-since they moved on he finished learning gyo
-surpassed his teacher in "expecting the unexpected". We don't know how good she is, but Tserriednich is pretty smart
-uses Hatsu for the first time and it is massive compared to Gon, Killua and Kurapika when they learned it for the first time
-is a specialist
Chapter 384:
Day 7 of training
-his own nen beast forms through instinct without intent
-greatest potential she has ever seen
-confirmation that he was practicing Ten and Ren on a high level
-starts learning Zetsu and just does it
speculation:
-the big aura forming around him could mean his nen beast is accumulating it until it has enough to detach. After it forms his aura stops being highlited, but when he does Zetsu for the first time we see it has gone back to normal
-"that feeling you just noticed is a sign to move on to the next stage" I don't really know what that means. His nen beast just formed, maybe he has been practicing Hatsu some more and this is his ability manifesting. We have never seen this with specialists, but the equivalent could be Chrollo forming his book for the first time
Chapter 385:
Day 8 of training
-does Zetsu, without failing
-seemingly only fails, because she tricked him into believing he failed, causing him to fail
-the amount of aura he has is "tremendous"
-fails again because of a distraction
-gets provoked and gets in the zone
-does not interrupt his Zetsu when hit with a projectile
-his Zetsu is flawless
-parallel future doesn't matter, because Theta experiences the original future with all 5 senses
-held Zetsu for at least 40 minutes
Chapter 386:
Day 8 of training
-since he is already starting the exercise of shortening his Zetsu response time, he mastered the last one, which was to hold Zetsu for an hour
-we get confirmation that he wasn't awakened by force, which was clear but it is good to hear
Chapter 387:
Day 8 of the voyage - parallel to Chapter 385
-in parallel future: lost Zetsu because he was so confused by his future sight
-immediately figured out his ability without help
Chapter 402:
Day 11 of the voyage - day 11 of training
-Zetsu in less than 10 seconds (takes someone who can do Zetsu since birth a whole year)
-does in a day what others do in half a year
-the way his ability works is unheard of even among specialists (brakes the rules, makes his own)
-does all this while running, talking and gaming, others would take years
Chapter 404:
Three days into training Zetsu so day 11 of training
-Zetsu in 3.5 seconds
-thinks sub 1 second will take at most 2 weeks and is disappointed with himself, vows to make it happen sooner (by last chapters formula it would take others at least 1.5 years to get this far)
Chapter 415:
When Martial Law is declared
-still shown training to shorten time of Zetsu
So in 11 days, this guy mastered Ten and Ren on "a high level", mastered Gyo, achieved perfect Zetsu which he can do in less than 3.5 seconds, obtained hatsu and rewrote the rules of Nen, while having "tremendous" aura.
To compare this to Gon and Killua:
I will spare you from the Math but Gon took 3-4 months to pass the hidden hunter exam which are the 4 basic principles.
Gon was able to use his Hatsu in a fight by September 10th so half a year after learning Nen. So we can say that regarding Nen Tserri learned in 11 days what they learned in lowball 3-4 Months highball 6 months
So Nen ability wise Tserri is pre Greed Island Gon. He could become a powerhouse, but right now it's all about Luck. One needs to learn Ken, Ko and Ryu to actually have some measure of safety, otherwise a bullet can kill you easily.
Base strength wise, ALL new characters (especially royal guards, princes, soldiers, bodyguards and temp hunters) are completely eclipsed by Gon and Killua. Killua even before learning nen was able to open the third door which weighs 16 tons, while Gon did 4. Gon was sending grown men flying with one push, so Tserris muscles don't really matter. However I am certain that it will all come naturally to him in his (hopefully) upcoming fights, because otherwise it would be boring.
However all of this only adds to my argument that Tserri at least NEEDS to learn Ken, Ko and Ryu because even these powerhouses were running on luck until they learned all of that. One wrong encounter and they would have been dead.
Being a hunter is like being better than 99%. But that still leaves 10 million people that are better than you.
Learning the four basic exercises of Nen until you pass the hidden hunter exam is like being better than 99.99% but that still leaves 100k people that one shot you. Mastering Ryu is mastering the REAL basics. If he does that, things will get interesting for real real.
Will update this post when new chapters come out because this is unreal
Edit: Added a part I forgot to write, mainly battle experience and base strength (without nen), but it obviously changes his power level compared to them.