Yuta Rika and Riki

Yuta is calm and composed normally and is kind
Yuta is the better fighter for more long range or careful fighters
Yuta has some access to his Copy technique which lets him copy abilities of Techniques temporary
Yuta is a man wearing a white jacket that is buttoned up and black pants and white shoes and his skin is decently pale and he some eye bags under his eyes and he has short black hair and he is 5 feet 11 inches tall and he has a katana in a katana sheath on his back and he has a necklace with half a heart and he is 17 years old

Rika is the opposite of Yuta with Rika being more flat and bland but dangerous sounding and Rika is a lot more murderous and has a bit of a temper
Rika is better against more closer range aggressive fighters
Rika has some access to her Storage technique which lets her store items with cursed energy in a pocket realm that Rika can access anytime
Rika is a woman wearing a black jacket that is buttoned up and black pants and white shoes and her skin is a bit pale and she small eye bags under her eyes and she has kinda long brown hair and she has some curves and she is 5 feet 2 inches tall and she has a katana in a katana sheath on her hip and she has a necklace with half a heart and she is 17 years old

Riki is kind and friendly but can be brutal and is very protective Rika and Yuta and does not want them hurt to where Riki will kill anyone that trys but Riki will also hold Rika back if needed
Riki's speech is slow and has a faint echo example: ("Yuuttttaaaaaa Rikkkaaa") or ("Leeavve frieennddss alloone")
Riki has full access to Copy but has to eat a limb of someone with that technique to permanently use abilities from that technique but only one at a time and Storage where Rika and Riki share the same pocket realm but has his own Technique called Charger which lets Riki charge Cursed Energy into his fists or attacks but also can charge attacks of allies and can release a massive energy discharge in the form of a massive 2 meter big energy beam that shreds through things and Riki's cursed energy is a black color and that black color appears whenever he charges his own attacks or attacks of allies and Riki basically has infinite cursed energy that Rika and Yuta can use when Riki can fully manifest
Riki not manifested is just invisible when Riki is partly manifested only head and upper arms can be seen and is half the size when fully manifested by Yuta and Rika combining their necklaces Riki is a 12 feet tall all white being with four lanky arms and has no legs with its legs being dark gray and it has no eyes with lines where its eyes should be and it's has a large mouth and it has two wing like shapes on its back and has rib cage like shape on its torso and has bone like shapes on its arms and body as plating if sorts

Yuta Rika and Riki first made as kids at a hospital for sicknesses they had cured where Yuta and Rika were 10 years old and Riki was 9 and they became friends after hanging out and playing and one day Riki gave Yuta and Rika necklaces his mom and dad had but never used which is the half heart necklaces they have and Riki said "No matter what we will be friends!" and Yuta and Riki agreed but then one week later Rika ran into the road to grab a cat and a car came in drove by a drunk man but then Riki saved Rika by pushing her out of the way killing himself and from the grief and cursed energy of both Yuta and Rika Riki became a Shikigami under Yuta and Rika's control and Riki was 10 when it happened while Yuta and Rika were 11 when it happened so from that moment on Riki followed and protected Yuta and Riki by either stuffing bullies into lockers dropping bullies off ledges killing curses or Sorcerers and throwing people or things around like ragdolls

the universe this all takes place in where Cursed Energy is made of emotions and the soul where everyone has it but it can leak out of normal people during negative emotions but there are people called Sorcerers that can use cursed energy to use Techniques which are powers there are also beings called Cursed Spirits or nicknamed Curses they are beings of cursed energy invisible to normal people and Curses only want to kill people and Sorcerers kill these curses while protecting people but Shikigami are and there are Maximum Techniques which is basically the strongest ability of that Technique (Only Riki has a Maximum Technique which is his massive beam of cursed energy called "Full Energy Discharge" which would leave a normal sorcerer without cursed energy for a while but because Riki has infinite cursed energy it does nothing to him) and there is Reverse Cursed Technique nicknamed RCT which is made by combining Cursed Energy with Cursed Energy making Positive Energy which can heal wounds but can kill curses nearly immediately (Yuta Rika and Riki has RCT) and there is Cursed Technique Reversal nicknamed CTR which is made by using positive energy for techniques (Yuta Rika and Riki do not have CTR) and there is Domain Expansion which is a domain that has a sure-hit effect that only hits anyone but the one that opened the Domain (Yuta and Rika share a Domain Expansion because of Riki) and there are Extensions which are Extensions of the main technique (Only Rika and Yuta use Extensions when Riki is not fully manifested but all three have Extensions) and there are ways to defend against domains which is Simple Domain which is a weaker Domain Expansion where anyone can walk in or out but can be coded to do somethings and the Simple Domain gives temporary defensive against Domains because they will break eventually but there is Domain Amplification which can defend against the sure-hit effect or make the domain stronger (Rika and Yuta have both)

there are levels to curses and sorcerers which Grade 4 to Special Grade and there is Semi Grade 2 and Semi Grade 1 and Semi Grade 1 to Special Grade Curses can use techniques and normally its only Grade 4 to Grade 1 but there rarely is cases where a Curse or Sorcerer becomes Special Grade (Yuta Rika and Riki are all Special Grade) and there are only 4 Special Grade Sorcerers who is Gojo Yuki Yuta and Rika there was a fifth Geto but died and got taken over by a Special Grade Curse and there are 5 of those with four of them being Disaster Curses which are Curses based of disasters which is
Jogo: Volcanoes\Fire
Hanamai: Nature
Dagon: The ocean
Mahito: Humans themselves
and Jogo can control lava and fire and Hanamai can make plants attack for her and Dagon can shoot out water or control fish and the most dangerous Mahito can reshape the soul of people which can kill people or make them Transfigured Humans which are humans turned into Curses and RCT can't heal people that Mahito has effected and all four Disaster Curses have Domain Expansions and the fifth Special Grade is Kenjaku which is brain that takes over dead people to gain their technique but also take over the body and is in control of Geto's body currently and there are Higher-ups that control Jujutsu Society the society every Sorcerer works for and there is people that can see curses but don't have techniques and they are basically politicians and there are Sorcerers with zero Cursed Energy or have a lot of cursed energy and are weak and they are beings with Heavenly Restrictions which either remove Cursed Energy and give higher combat power or give Cursed Energy for weaker combat power and there are Binding Vows which can give something but also remove something like can make you stronger but you can't use as much Cursed Energy as you used to and people can make Binding Vows with others and what happens when someone breaks a Binding Vow? no one knows

Riki acts as bridge between Rika and Yuta which is why they both get access to Riki's infinite Cursed Energy when summoned but also why they both get full access to their techniques when fully summoned and is why Yuta and Rika share a Domain Expansion
Riki is technically classified as a Special Grade Curse
when both Rika and Yuta first joined Jujutsu Society for school a execution was put on them temporary but every attempt to kill Yuta or Rika failed because of how protective Riki is and Rika and Yuta tried to killed themselves to get rid of Riki but Riki stopped them and assured them that he is still himself
Both Yuta and Rika started as Special Grade Sorcerers because of Riki
Rika is jealous if Yuta talks with a girl

Yuta:
Copy Technique
RCT
Domain Expansion and Domain Amplification
Simple Domain
Overall good strength
Rika:
Storage Technique
RCT
Domain Expansion and Domain Amplification
Simple Domain
RCT
is better then Yuta at hand to hand combat but around same overall strength
Riki:
Copy Storage and Charger Techniques
Infinite Cursed Energy
Flight because of the wing shapes on his back (they are small but strong)
Super Durable because of bone like plating
Super Strong because of four arms and just being strong overall
Very fast because of the wings on his back but can go faster by charging his wings being able to out speed a fighter jet
RCT
Can sense when Rika and Yuta are in a lot of danger because of his connection to them but will stay if was commanded