(WARNING: Hikari's origin happens during the canon of Panty and Stocking with Garterbelt, you need to watch the anime to fully understand this.)
So there he was... Hikari Kibago and his brother Kotakunaoru walking on the outskirts of Daten City. Hikari Kibago used to be called Kurai Kibago since he was a dark pokemon, which are pokemon transformed by demons. At the time there were no light pokemon, and Kurai and Kota were heading into Daten City, looking for an answer to lift this dark curse from his race.
He heard that he needed mystical items called heaven coins to lift the curse. The two brothers headed to the museum to get a chest to put the coins in. So they do and try to carry it to somewhere safe. When suddenly they were ambushed by pokemon ghosts, which are dark pokemon who completed their transformation. The gang of ghost pokemon was led by a ghost luxray, he was looking for them to prevent them from collecting the coins. So a chase ensued, which lead the two brothers into a church.
There they saw Garterbelt talking to Panty and Stocking, the two rushed towards them trying to hide from the gang of ghosts. But the ghost luxray followed them, and Kurai and Kota fought off the gang of ghosts and Garterbelt questions why they came to the church and thinks that they led the ghosts inside. The two explain themselves, saying that their mission was to collect heaven coins to turn his race into their former selves.
It was a coincidence since the Anarchy sisters were collecting heaven coins to get back into heaven. So Kurai insists that they work together, with the brothers hunting the pokemon ghosts and the sisters hunting the other ones.
So later the four head towards the ghost "Giant Brown", strangely accompanied by a ghost muk. So the brothers defeat the muk and the sisters defeat Giant Brown. The muk was worth about 10 coins since ghost pokemon are MUCH more powerful than other ghosts.
In "Death Race 2010", Kurai and Kota follow the Anarchy sisters to pursue Crazy Crazy Cabbie who was accompanied by a ghost latias and latios. So the brothers fight the ghost eon duo and later Stocking unknowingly slices off latias' wing, killing it. The ghost latios gets infuriated and tries to shake Kota off his back, in which Kurai flies up to him on a pidgeot and assists him. So the ghost eon duo are defeated and were worth about 50 coins.
In "The Turmoil of the Beehive", the brothers follow the Anarchy sisters throughout the school and eventually see Queen Bee in her human disguise, but they notice a rather big bee flying around her. Later on the large turns out to be a ghost beedrill, so the brothers have their fight with the beedrill and his army of ghost combees. The beedrill itself was worth about 40 coins.
In "Sex and the Daten City", Kurai starts to become infatuted with Stocking, with Kota find it kind of odd. Later at the theater they run into an old friend who is a dark nidoking named Shimo. Shimo was shocked that the two managed survive the journey out of hell, but agreed to help them. They also meet a new face who was a salamence named Anteno, along with other new faces such as a pikachu named Volt and two dark deinos named Supai and Snupu. While the girls headed out to destroy the porn tapes, in the apartment the group of pokemon tried to discuss what they could do to help Kurai and Kotakunaoru reach their goal.
In "Catfight Club", Kurai follows Stocking while Kota follows Panty. When Stocking was led into the back alley by Gal Goul and Bloody Hound, Kurai was swiped away by a ghost zangoose who was working with a ghost seviper. He tries to fight them off but gets severely injured. Kota comes in and fights with Kurai but both get severe injuries when the ghostly duo get killed. They received 70 coins from the fight though, but luckily picked up by the Anarchy sisters and got their wounds treated.
In "Pulp Addiction", the duo go with Panty and Stocking to a paper factory where the brothers encounter a swarm of ghost ninjasks. They get defeated and were worth 60 coins each.
In "High School Nudical", Kurai explores more his infatuation for Stocking and he and Kota encounter a ghost deoxys (speed forme) that was running with Secret Speed Star, the deoxys is defeated and was worth 100 coins.
In "The Runny", the brothers were disgusted by the fad of nose picking and went with the Anarchy sisters to Ugly Snot's blimp. There the brothers encounter a ghost drowzee that was worth about 55 coins.
In "Les Diaboloques", they meet Scanty and Kneesocks, and find the pokemon ghost stone alongside the other ghost stone, they take the pokemon ghost stone while the Anarchy and Demon sisters are fighting each other and break the stone. But the stone was guarded by the ghost creation trio (Dialga, Palkia, and Giratina). They engage in battle with the trio with Shimo, Snupu, Supai, Volt, and Anteno assisting them in the fight. So they defeat the trio and acquire over 2000 heaven coins! Then the voice of dark arceus thanks them for breaking the curse, and the only thing left now is to offer up their heaven coins. But they have a long way to go before that happens.
In "Trans-homers", a ghost reshiram and zekrom are rampaging through the city and the brothers pursue the ghosts with the help of a dark kyurem and Shimo. So they eventually subdue the duo and the dark stone and the light stone get absorbed into Kurai and Kota's body respectively. Allowing them to use their power. While the dark Kyurem reverts into the god stone and gets absorbed into Shimo's body, allowing him to use Kyurem's power. Back at the church they find Panty and Stocking quarreling and a gang consisting of a ghost bisharp, garchomp, and scizor attack the brothers. The trio is defeated and were worth 200 coins.
In "The Stripping", the two brothers practice their new powers and go with the Anarchy sisters to the casino where a ghost honchkrow was helping the demon sisters with their plans. The honchkrow tries to stop them with his mob of ghost murkrows but ultimately failed and help Kota and Kurai earn about 90 more heaven coins.
In "Of the Dead...", a ghost skarmory hunts down the brothers as they help the Anarchy sisters fight off the zombies. The skarmory was defeated at dawn and was worth about 200 heaven coins.
In "1 Angry Ghost", a ghost cacturne stalks the brothers as they watch the trial of the Anarchy sisters, and when Wife Petter revealed the truth the cacturne ambushes the brothers but was ultimately defeated by Kota's fire fang. The cacturne let out about 20 heaven coins.
In "If Angels Wore Swimsuits", the brothers go with Panty and Stocking to the beach and face off with a ghost armaldo and cradily. They also faced off with a bunch of ghost water pokemon when the demon sisters transformed the sea creatures into ghosts. They earned about 3000 heaven coins when they defeated the ghost sea pokemon which included multiple gyrados, wailords, tentacruels, and other ghost pokemon.
In "Ghost: Phantom of Daten City", Kurai was shocked that Stocking had her eyes set on Patrick Fagry. So he spies on their date and was flabbergasted that such a lovely girl would be into a loser like that. And so time went on and Kurai goes with Panty to try and talk to Stocking, but then Patrick puts the ring on Stocking's finger and Kurai's heart was destroyed, he went back into the apartment and cried his eyes out. And soon he believes that he'll never have a chance at Stocking, but he still hung with her as her lapdog at times.
In "Panty+Brief", Kurai and Kota finally face off with the ghost luxray, they got 500 heaven coins and were told by the dark arceus that they finally acquired enough heaven coins and the time has come.
In "Bitch Girls 2 Bitch", the brothers go with Panty and Stocking to stop Corset's plan of opening Hell's gate and when Corset was defated by Mother, the dark arceus showed himself descending from the heavens. The arceus then gathered their heaven coins and absorbed them transforming into light arceus, letting out a cry and using judgement to turn the dark pokemon into their former light selves, thus turning Kurai into Hikari Kibago. The arceus offers them the ride to the church and drops off the brothers.