(Update: the old list needed a huge revision after i dove into depth of some other stuff.)
1. Tier (High Hyperversal,Possibly Low Outerversal) Hecatia, stated to be the strongest character in touhou. Self-explanetory. However gods in touhou are not bound by ANY concepts this includes the concept of dimensions thus they are above most structures a normal verse would follow. They have a higher existence thus making them more powerful.
2.Watatsuki Sisters (High Hyperversal) - the Watatsuki sisters ARE stronger than Yukari. Yukari herself said no one on Earth can beat the Lunarians (which is why she didn't even try to fight Toyohime):
“The Lunarians possess highly advanced technology, unyielding stamina and abilities that are far outmatch those of youkai. The ones living on Earth can never beat those on the moon, especially in the lunar capital.”
...and ZUN confirmed it in an interview, so she wasn't just lying:
"My thought is that the Lunar Capital is where the highest, noblest gods live. [...] Because of that, as far as anyone from Gensokyo goes, the Watatsuki sisters are truly untouchable as a necessary measure." https://en.touhouwiki.net/wiki/Symposium_of_Post-mysticism/Interview
And it makes sense because Yorihime basically has the same ability as Yukari (via summoning the god of boundaries) in addition to also having the powers of the other 8 million gods, unlimited stamina and no life/death border. Toyohime's ability isn't clearly explained but it's implied to be some kind of probability manipulation so that's probably why Yukari can't beat her either.
"From a quantum point of view, possible events will absolutely always happen. This is because in the quantum world, everything is decided by probability, but it's impossible to capture that probability with exact precision. As long as an unrealized event has a non-zero probability, no matter how low it is, it will occur at some point. Since the universe is built on quantum phenomena, it's not all that unusual that living things from Earth should find their way to the moon. After all, that's how even we came to live on the moon."
"Right away I understood Lady Yagokoro's lesson, and now I am one of the very few who have ever had the ability to bind together Earth and the moon, who have the power to go back and forth between them at will" https://en.touhouwiki.net/wiki/Cage_in_Lunatic_Runagate/Third_Chapter [ Credits to ViridianBlue on Youtube for this info ]
3. Yukari time (High Hyperversal) - I'm going to use the explanation I usually use on youtube.
(In Perfect Memento in Strict Sense, yukari is stated to be easily able to undermine everything in reality and her ability is defined as one that allows both creation and destruction https://imgur.com/a/PGDEqIC and can freely manipulate every existence http://tasofro.net/touhou155/manual/chara18.html#top . Additionally she can control all boundaries and remove all boundaries https://imgur.com/a/0M8RuPA which would include the boundary of red-white which represents the beginning of all things that being existence and nothingness itself https://imgur.com/a/h09SR0X . This is important due to the fact that Touhou follows brane cosmology https://imgur.com/a/UU7ueDj and string theory https://imgur.com/a/6ciIQBq . And seeing as to which the branes fall under string theory https://en.wikipedia.org/wiki/Brane , this should justify string theory existing more since no other related theories other than string theory was noticed, alongside the fact that Renko was the one who noticed these phenonemons https://en.touhouwiki.net/wiki/Dr._Latency's_Freak_Report/Story ).
Further more, the string thereoy that exist in touhou is Hilbert Space
In Changeability of Strange Dreams, https://en.touhouwiki.net/wiki/Changeability_of_Strange_Dream/Story
Outside World is said by Merry that it follows String Theory https://imgur.com/a/PUB5g
But then, Yukari is implied to have manipulated the Boundary of Wave and Particles in Netherworld (but it's still sort of related to Gensokyo as it being separated by just a Boundary of Death and Alive isn't enough to separate the particles). https://imgur.com/a/22fP7
Manipulating that proved the existence of wave-particle duality. As the Boundary is the duality of Wave and Particles https://en.m.wikipedia.org/wiki/Wave–particle_duality
If my interpretation is right,such duality shouldn't exist in String Theory as the presence of Wave and Particles contradicts the existence of strings.And It would correlate to Wave function as all the information about a particle is encoded in its wave functions
In Dr Latency's Freak Report, https://en.touhouwiki.net/wiki/Dr._Latency's_Freak_Report/Story
Shits get interesting here.Really interesting.
Gensokyo is referred as an another brane world dominated by different types of particles. https://imgur.com/a/AKMOL
It being stated as a brane world evidences it being a 4D structure and all the way up to infinite dimensional.
"The central idea is that the visible, three-dimensional universe is restricted to a brane inside a higher-dimensional space, called the "bulk" (also known as "hyperspace"). If the additional dimensions are compact, then the observed universe contains the extra dimensions, and then no reference to the bulk is appropriate. In the bulk model, at least some of the extra dimensions are extensive (possibly infinite)" https://en.m.wikipedia.org/wiki/Brane_cosmology
Schrödinger's cat is stated to be applied to Gensokyo as stated by Merry https://imgur.com/a/K4Ksu
"Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935.It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanicsapplied to everyday objects. The scenario presents a cat that may be simultaneously both alive and dead, a state known as a quantum superposition" https://en.m.wikipedia.org/wiki/Schrödinger's_cat
Schrödinger's Cat proved that the Wave Functions are in a superposition state.
"In quantum mechanics, wave function collapse is said to occur when a wave function—initially in a superposition of several eigenstates—appears to reduce to a single eigenstate (by "observation"). "
"Calculations of quantum decoherence predict apparent wave function collapse when a superposition forms between the quantum system's states and the environment's states. Significantly, the combined wave function of the system and environment continue to obey the Schrödinger equation." https://en.m.wikipedia.org/wiki/Wave_function_collapse
"According to the superposition principle of quantum mechanics, wave functions can be added together and multiplied by complex numbers to form new wave functions and form a Hilbert space" https://en.m.wikipedia.org/wiki/Wave_function
Wave functions of Gensokyo are in a state of superposition which is a infinite Dimensional Hilbert Space.
Moreover, Gensokyo is directly referred as a Quantum World https://imgur.com/a/0vcop
"In the quantum world, things get really, truly wrong. Here we have spaces of infinite dimensions, by necessity. Spaces of possibilities" https://motherboard.vice.com/en_us/article/539kdb/life-in-infinite-dimensions
So infinite-D Gensokyo is a thing now?
No Common sense https://imgur.com/a/c8P2y
What theory does the Outside World follows again? https://imgur.com/a/PUB5g
What's the definition of Gensokyo again?
幻想郷- Land of Illusion/Fantasy.
What's the Boundary of the Great Hakurei Barrier? Boundary of Fantasy and Reality
Welp.I guess ZUN put a lot of effort trying to put this in.Gensokyo is a fantasy land which is apparently an infinite-D Hilbert Space as opposed to the Outside World which follows a 10D to 24D String Theory (Depends on the context of the theory).Since it is a fantasy land,it's only logical to defy scientific logic (lol) and guess what,different than the Outside World,it follows a different type of dimensional theory.
4. Junko- (Complex multiversal to high hyperversal) Pure mama junko was stated to have fought on par with with the watatsuki sisters prior to the events of LoLK (Touhou 15). Also her ability is described to give birth to the gods as she can purify anything. Junko's purification brings things back to their godly nature , before they had names, or even bound to any concepts so it could be considered an ability to destroy any concepts)
5. Doremy Sweet (High Complex Multiversal)- The Ruler of the dream World. The Dream World is an infinite dimensional world. Holding countless/infinite dreams. These dreams are referred to as otherworlds. Otherworlds in touhou all have their own space time continuum making them seperate universes. Doremy is able to control all dreams and is able to erase them, eat them, and create them. She's also a reality warper as dream manipulation directly affects reality in Touhou. Even though it's vauge it makes a lot of sense as she is regarded as the most dangerous youkai in the dream world. As everyone has a dream counterpart (except the gods and several other exceptions) they are logically below her.
6. Okina Matara (Complex Multiversal)- Okina Participated in the creation of Gensokyo . Gensokyo is a brane world https://imgur.com/a/Lnd97
which is 4D to infinite-D Gensokyo is a quantum world which is infinite dimensional https://imgur.com/a/9eD6w . Quantum world is also space of possibilities as stated by Yorihime which is also infinite dimensional https://imgur.com/a/qIEV9. Okina also claimed that she can recreate Gensokyo as a whole https://imgur.com/a/dIGe6
7. Yoragami Sisters (Shion and Joon) [High complex multiversal] - Overall Her Perfect Possession was controlling and screwing up the whole Dream World as a side effect
8. Sagume Kishin (Complex Multiversal) When she speaks about a particular situation or event, that situation will eventually proceed to reverse itself, through whatever means possible. If she speaks about an attempt to achieve a goal, it will fail in some way. If she speaks about something bad occurring, it will be resolved in some way. Due to this, she tends to not speak too much and always chooses her words carefully. Note that it is the situation or the event she talks about that will be reversed in some manner; it is not that the opposite of what she says must occur.
She's also Using her powers, created a secret occult ball. It had the power to change the world by using people's words, and merely being near it would cause false rumors, such as urban legends, to materialize. Although it was just insurance, the plan was to use it to materialize the Lunar Capital in Gensokyo by spreading rumors about NASA hiding the truth about what they saw on the Moon. This also caused numerous lesser urban legends to materialize, starting the events of Urban Legend in Limbo.
9. Remilia Scarlet (Multi-Universal via fate hax) - Remilia holds the power to manipulate fate. The Future is implied to be not predetermined https://imgur.com/a/gpBBD , meaning that she logically "creates" future as she manipulates fate. Creating future can be said to be altering probabilities
Her strength of an oni too is tremendous as Suika an oni whose attack shattered all of Heaven. Remember she effortlessly shattered the heavens with ease, which are referred to as "paradise", the realm where Amitabha, who is googolplexes larger than the observable universe lives. Amitabha has been calculated to be 3.7107x10^152 universes large.
10. Sumireko Usami (Complex multiversal) - Remember her yeah I do too. Her nearly breaking the barrier of gensokyo would've practically destroyed gensokyo from existence though she is still quite inexperienced in fighting she can hold her own against peeps like marisa and reimu.
Anyway hope you enjoyed the new list it took a while to revise it but if you have a disagreement just contact me and i'll see. Thanks and bye!