Phoebe became more of a Jerkass in the later seasons because she couldn't over the deaths of Grams and Prue
Billie was born from the Nexus being destroyed.Billie is a reality warper and has all sorts of powers despite her young age. She also appeared out of nowhere at the beginning of the eighth season. She could have been born from the Nexus energies and used Prue as a basis to get close to the sisters. She might have also created a connection with Paige to become her charge. Billie then created a past for herself so that she would connect to humanity easier. After being exposed to the sisters and feeling angry at their selfish ways, she subconsciously created Christy and even manipulated demons to think that they had held her captive for years.
Charmed takes place in the "Ultimate" style universe of SmallvilleThis theory was somewhat confirmed by one plot point of either a season 6 or 7 episode which had Wonder Womans girdle. Actually Hippolyta's girdle which was found by Billie in a chest of previously unknown magical artifacts and in a short bit of Exposition Hippolyta's youngest daughter (aka Donna Troy/Wonder Girl in the comics) tried to wear the girdle but was destroyed by its beyond awesome level of magic. Billie tries on the girdle herself and nearly dies herself. To boot the costume generated by the Girdle as Billie puts it on looks suspiciously similar to a image from a 2005 or 6 Wizard Magazine issue which has a Alternate Universe Wonder Girl costume which according to the related article came from a "Ultimate" DC Comics universe which was an offshoot of TV series Smallville. And as a final nail to the foundation both Smallville and Charmed were CW/WB network series which while it never happened a Crossover could have been a possibility although this would have been Hilarious in Hindsight as Clark would have most likely become the designated Damsel in Distress due to his physical weakness to magic in which the Halliwell sisters would have to bail him out of constantly.
The Triad has Cole's father's soul because they wanted to stop him from being reborn.Reincarnation is mentioned frequently in the series. Phoebe also says that Cole's father had done a lot of good things when he was alive. The Triad (or the Source, or some other demon) could have intercepted his soul after he died to prevent him from either becoming a Whitelighter or being reborn and doing more good in the world. Cole could have made his deal with the Triad so he could release his father's soul.
Charmed is the imaginary adventures of three girls playing with their Barbie dolls.This is why so many of the Charmed Ones's crushes and love interests are lantern-jawed white guys - they're Ken dolls.
Prue was destined to die from the start by the EldersThe Angel of Death basically tells her she's destined to die in S3, which seems odd in retrospect (why would a Charmed One be destined to die from The Powers That Be?) but less so if you consider the following: Piper and Leo already showed in Styx Feet Under, S8, that cheating death is impossible; if he's really out for you, its only a matter of time. Prue had a really sharp concentration of near death expeiences in her tenure, nearly dying in The Power of Two but before being given CPR by andy, to the S2 finale (where she's stabbed by the dragon and then rezzed, something which this troper imagines would also further p*ss Death off, further giving him cause to go after her) to the S3 finale (where Leo first heals her) and then finally in S3 again where Death finally catches her. Just as in S8, Prue may have been slated for death so that the bereavement would act as a motivator for the sisters to kill the source, which it did, as they planned for Leo.
The Smexy Genie from the S2 finale was at least partially responsible for Prue's final death in S3Think about it: Genie wishes are notorious for being complete monkey paws (even when the genie isn't trying to be a jerk) and this is demonstrated throughout the episode multiple times. Hence wouldn't it be logical, even natural, for her resurrection wish to also backfire, say, by only granting Prue temporary resurrection before being killed off again in, say, the next season finale? This would explain why she couldn't be saved from Shax even by time travel and why Death told her she was destined to die then.
The Sisters Don't Do Ritual Spellcasting Because They Don't Need ToThe in-verse reason the sisters gradually become less dependent on ritual (like we saw for most of the Burge era) is because - being the most powerful witches ever to exist - they are strongly magical enough not to need to build up ritual energy to cast spells. Likewise, as the series progresses they become stronger and stronger witches and so by the end all they need is a quick rhyme and they're good to go! Compared to the first episode for example, "Something Wicca This Way Comes", which was relatively very ritual heavy (in fact, despite being new witches, they probably didn't even need to do as much as they did & were most likely being - understandably - overly cautious). Other normal, magical witches would probably have to go through a relatively complicated series of processes to achieve some of the feats the sisters have with just some hocus pocus, like casting an illusion on every man on the planet in "Styx Feet Under".
The Elders and/or Angel of Destiny killed GramsPretty self-explanatory - we saw in Pre-witched that she was about to stop the sisters from inheriting their powers before she just so happened to have a heart attack. Coincidence? I think not.
The Elders can only bring someone back from the dead (as whitelighters) once, or elseHey, it would explain why Natalie had to die (other than angst, obviously).
Prue created the Cleaners.The Cleaners have not done anything until they first showed up and they have the power to alter memories. Prue could have been worried that exposure of magic is much easier now with all the technology and so she got the Elders and the Demons to create the Cleaners. But, to give the Cleaners more credit, they made it so that they were at least active for eternity when in reality, they were around for only a few years.
Andy became a whitelighter.Leo's first wife told Piper that he dreamt about Leo after his death. Kyle also said goodbye to Paige. The scene where Andy says goodbye to Prue is eerily similar to the situation described by Leo's first wife.
Higher forces were responsible for Piper and Phoebe's career successes.Because the forces of good wanted to make sure they had enough money to keep the house.
Coop, or some other Cupid, was responsible for Phoebe's relationship with Cole being a failure.After the Source was gone, everything would have worked out fine if Phoebe had been willing to use the resurrection spell so Cole didn't have to gather demonic powers, or if they had been able to strip his powers without empowering some other demon, or just if Phoebe hadn't taken a level in jerkass. We've seen that Cupid rings can be used to not only encourage someone to enter a relationship, but also to steer them away from relationships. We also know that at least one Cupid turned a mortal woman's love away from a demon (Drazi) and towards someone else. Phoebe suddenly hating Cole in Season 5 was the result of a Cupid who thought her being involved with a man who had previously been the Source was a very bad idea, who kept entering Phoebe's mind and hissing "He's evil, he'll always be evil, tell him to leave you alone!" everytime she saw him. Coop might have had his eye on Phoebe long before he met her and orchestrated her entire rejection of Cole in an effort to Murder the Hypotenuse. Evil Twin (both freeze things), Stormy is Prue's but lost primogeniture to Icy and telekynesis to Darcy in two separate bets and had to recycle herself, and Darcy is Phoebe's Evil Twin (her original power being setting things on fire in such a way that nobody, not even Bloom, can put it off without fairy dust, but using telekynesis to brag she's smarter than the older sister).
At some point in the future, at least one of the Charmed Ones screws up big time......And it results in electricity around the world just disappearing. In other words, the Charmed Ones cause the events of Revolution by misuse of their magic. Nice job breaking it, heroes.
Phoebe's boss/friend Elise and Aviva's aunt Jackie from "The Fourth Sister" are one and the same.First off, they're both played by the same actress, Rebecca Balding. That's where the theory starts. Secondly, the only Halliwell that ever saw and talked to Aunt Jackie in "The Fourth Sister" is Prue. Elise and the Bay Mirror first appear in Season 4. After Prue got on the bus called "Dead". This in turn means any retcon to this effect would not breach continuity. Now for the evidence that makes this actually plausible. Look at Elise. She's the typical example of a woman who sacrifices her personal life for the sake of her career and goes on to regret it years later—and this is established canon, as she openly tells Phoebe this at one point imploring her not to repeat her own mistake. In fact, no family is ever mentioned when it comes to Elise aside from her ex-husband who was apparently a schmuck—not even in the Charmed Comics. Now look back at "The Fourth Sister". Jackie is completely alone. The only person there to keep her company is Aviva, and it's clear that this is only because she's taking care of the girl until her mother gets better, and that Aviva hates her guts, and that she doesn't even understand why. She also refuses to call her mother when Aviva gets upset. From that, one can only assume she's more used to keeping distance in her relationship with her family than Aviva is at the time of the episode, and Aviva does not like this—which only makes the sorceress Kali's attempts to influence Aviva that much easier. If, by the unlikely chance, an all-grown-up Aviva ever resurfaces in the comics, expect at least some allusion to this if not a full confirmation. If this is fully confirmed, expect to learn that one of the two names, Jackie or Elise, is probably her middle name. Most likely Elise, as it's more common for family to use first names with someone who goes by middle name in public than the other way around. If Aviva's mother aka Jackie/Elise's sister appears as well, she may look similar to Alberta Watson, the Canadian actress who plays a character named Madeline in both Nikita television remakes.