Billmore Hawkins and Reimu Hakurei: Both are the protagonists of each original game and rivals due to have the same personalities, which are considered heroic like investigating their respective places and constantly exterminate hostile creatures (space monsters/aliens and Youkai respectively) anywhere they go. Billmore is an American infantryman who formerly became War on Terror survivor and currently working as an operative of the democratic military organization known as the Investigate Force, while Reimu is currently a maiden of her own shrine set in Gensokyo. They also have their important mentors in training: General Baxter for Billmore and Yukaru Yakumo for Reimu.
Josh Celton and Marisa Kirisame: Both are the best buddies of each main character or protagonist. Josh is the I.F operative who is befriended with Billmore as his best friend after leaving his respective hometown of origin in Europe, while Marisa is a witch and now a best friend of Reimu after formerly became a minion of the evil spirit Mima. They also constantly exterminate monsters using their abilities in their respective places.
Sam Ramsen and Sanae Kochiya: Both heroines have the daughter of her deceased father versus the descendant of the goddess rivalry. Sam specializes her stealthy investigation to find the way in avenging her father's death for her respect to General Baxter as a detective, while Sanae has the ability to manipulate the wind element as her goddess did in the same shrine, but her form is not native to Gensokyo.
Rina Stock and Sakuya Izayoi: There must be a rivalry between heroines, the Irish-born assassin and the housemaid. While Rina became a member of I.F and has mastered the art of special force training of both military weapons and assassination, Sakuya is the only human who lives in Scarlet Devil Mansion and has an ability to manipulate the time as she is fully skilled with knives.
Axl Jet and Yuyuko Saigyouji: Both Axl and Yuyuko are most likely rivals due to their own laziness but differently cheerful, friendly and kind. Axl is used to be a computer programmer for his interests on any kinds of software as his non-operational service and mercenary for fighting evil (e.g. jerks and weirdos) in a heroic way as an operational unit of the resistance and later Recom Hero Squad, even though he has hopes to do something in it for them. And Yuyuko, the departed ghost princess who committed suicide, often makes bizarre, apparently nonsensical remarks and sometimes seems to overlook the obvious, leading to her characterization as an airhead or a ditz. Also, both of them like to eat a lot of food.
Guy Rawkins and Tenshi Hinanawi: Guy and Tenshi can only be seen as rivals due to their hopes of strong natures and rather nice personalities. If there's something happened negatively, Guy, the first and fearless leader of Recom Hero Squad, has a cool mind in his heroic ways for a better future and always makes good at planning against incidents and other evil threats towards humankind, while Tenshi, the residing celestial, has absolute confidence in her playful effects of nature and gets mad for insulting them.
Gast Masken and Mamizou Futatsuiwa: Gast and Mamizou are very similar, and therefore are rivals in Psonic/Touhou universe. Both are the masters of disguise with their likes of transformations and themselves. Separately, Gast is a stealthy, enthusiastic German spy who can rely on sharper things and even abilities for espionage: camouflage, disguising himself into his enemy using his espionage PDA, hiding anywhere and going inside the prop. But later, he was wishing to join the Recom Hero Squad as an infiltration specialist or stealthy unit. And of course, Mamizou is a bake-danuki who morphs different things and herself and wishes to become the ally in the youkai forces.
Landon Trakes and Patchouli Knowledge: Both Landon and Patchouli accurately do everything with their sights but still make a lot of flaws sometime. Landon, the British marksman and camper, likes camping, negotiations, blade tricks and relying on accurate targets with his signature firearm called the sniper rifle and weapons for hunting down enemies in ranged combat, while Patchouli was being a librarian and can read only more books in order to get smarter as her main interest, even she can manipulate 7 elements: fire, water, wood, metal, earth, sun, and moon.
Carole Rogan and Remilia Scarlet: Carole and Remilia rival together for being respected by most creatures and said to have charismatic personalities. However, in reality, Carole has a lot of her adventures (as an adventurer) and mysterious investigations on several incidents to keep the humanity safe from any cause of danger (as detective/RHS operative), while Remilia usually only does it during incidents or for important matters due to the fear they have for her kind.
Voltrex and Cirno: Both Voltrex and Cirno are sometimes appeared to be morons but they were trying to become stronger and improve their intelligence to show technology versus magic rivalry. Voltrex, referred to its model number PXT-96 as part of Voltrex series of robots designed only for both service and combat, has more improvements to its intelligence, will manage entities when it detects offensive threats and is able to use its secret weapon systems in its abilities as being engaged in battle, whereas Cirno manipulates the cold power using her abilities and shows her strength to prove that she's the strongest for her kind, exceptionally matching the power of some weak creatures. If both have been interestingly opinionated the other way around, Voltrex will do anything regardless if its programmer is good or bad while Cirno is shown to be childish and quiet weak unlike most of Gensokyo's residents because of her stupidity.
Barris Lost and Hata no Kokoro: Barris and Kokoro are both considered rivals who wear any kinds of masks. Barris, the masked human-mutant hybrid mercenary for resistance, has a helmeted gas mask on his head to prevent various infections outside or inside even he slays many monsters with his weapons in combat for survival (paper bag in some occasions) while Kokoro, the Menreiki Youkai, relies on her masks to show her emotions to other beings, her facial expressions are emotionless and can be connected to poker face. They are also responsible for sharing their emotions, especially passions.
Kevin Abraman and Yukari Yakumo: Kevin and Yukari are wise masters of those who require more training and can be possibly seen to have tank commander of Recom Armored Division versus Reimu's mentor/employer rivalry due to their summons of vehicles: tank (which was coming out from the supporting cargo plane or any futuristic heavy aircraft) and train (which was coming out from Yukari's boundary). Kevin orders his army of supporters to protect Earth from a huge horde of aliens under their ordered control known as Xenorians and needs the dimensional device to warp from Earth to the alien homeworld Xenoria for defeating the evil mastermind behind the incidental situation until their missions are hopefully completed, while Yukari teaches Reimu not just about Gensokyo but also how to do her job as Shrine Maiden or gives her mission to investigate the incidents like in Subterranean Animism.
Captain Neo and Kaguya Houraisan: Captain Neo and Kaguya oppose to each other to have star fighter pilot versus immortal Lunarian princess for different galactic situations and abilities; Captain Neo, the top ace space pilot of the Planetary Alliance, is in the outer space where Terran face off against Hades Empire's potentially universe-destroying ordeals in hopes of saving humanity and can rely the original SVR fighter and manipulates the cosmic energy from the contact with Aegians while Kaguya Houraisan, formerly the moon princess, is on Earth (eventually be Gensokyo) now when ended up to live in Eientei and manipulates the power of eternity. Both of them have also came from their universal origins; Captain Neo is from the planet Earth and Kaguya is from the orbital satellite called the Moon.
Solo Breeze and Fujiwara no Mokou: Solo and Mokou are rivals of respective characters from Psonic/Touhou universe and can possibly oppose to each other. While Solo is an ace pilot of Planetary Alliance that enters another galaxy-destroying situation with the modified version of the original SVR fighter after Captain Neo's turn for a mean time, Mokou is a powerful immortal that earns her power through life and her immortal status since she can keep fighting with her fire manipulation until she can no longer stand the pain after drinking the Hourai Elixir 1300 years ago. They both also seem to bear the opposites of their relationships; Solo became a friendly rival to Captain Neo for giving him a chance to challenge his previous competition in space opera, while Mokou is very hostile to Kaguya for the same mess she was after so many years of exile, and so close to where she lived long.
Butch Coby and Aya Shameimaru: Both Butch, the anthropomorphic rabbit, and Aya, the crow tengu, have a street vigilante of Tycoon City versus interviewer of Gensokyo due to their likes of making wisecracking comments during danger and have been through bizarre and horrifying situations, Butch in a great violence of the Led Storm Gang, and Aya in the happenings of Gensokyo. They have also used their own things and skills to involve incidents: Butch has a bike for his rides and various forms of street fighting for preparing the protection against Led Storm Gang, and Aya has her camera for taking pictures on danmaku of every boss character and Bunbunmaru newspaper for writing exaggerated news reports about anything that happens in Gensokyo.
Aip Orang and Hatate Himekaidou: Aip, the anthropomorphic monkey, and Hatate, another crow tengu, are rivals because of such different imitations from their original counterparts with same things: Butch for Aip and Aya for Hatate. Aip uses a different style of street fighting compared to Butch, while Hatate never goes outside for her newspaper research and uses her ability known as thoughtography or Nensha instead. For their relationships, Aip befriends Butch as his partner and Hatate regards Aya as a rival photojournalist and competitor.
Son Goku and Ryu: Both of them were very popular from Japan, powerful and could attend in martial arts tournaments. Both of their antagonists (Piccolo, Beerus and more for Son Goku and M. Bison for Ryu) wanted to take over the world. Both of them also involve getting the important things that grant wishes: the Dragon Balls and Luck.
Jake and Deadpool: TBA
Sonic the Hedgehog and Rainbow Dash: Both Sonic and Rainbow Dash are very fast and originated from franchises that are kid-friendly even though they have a teenage/adult fanbase. Both of them are friends who are monarchs of their kingdom and became members of their groups, the Freedom Fighters for Sonic and the Mane Six for Rainbow Dash. Both of them had a darker and much serious counterparts, Sunset Shimmer for Rainbow Dash and Shadow the Hedgehog for Sonic.
Shadow the Hedgehog and Jin Kazama: Both of them are much more mature protagonists that are possessed by a secretive agency company, both of them have tougher female companions, Asuka for Jin and Rouge for Shadow. Both of them had dark powers, Devil Gene for Jin and Chaos Control for Shadow.