So far Barry was able to start regaining some sense of optimism that Zoom had taken from him before the season 2 finale and his responsibility since Jay Garrick, his father from Earth 3, was able to get him to understand 100% that changing events in the timeline, the consequences of time travel and that once an event is altered, it cannot be restored to exactly as it was before. Jay told Barry that he would need to learn how to live with the consequences of his actions and keep moving forward in which Barry finally agreed and does so.
And despite having the Reverse Flash help him reset the timeline back to the way it was before Flashpoint, enemies from that timeline including the Rival, Magenta and more that are on the way have been brought back into the current timeline by Dr Alchemy who along with his cult are awaiting Savitar's arrival and return as well as preparing Earth 1 for what he tells Joe and the SWAT that compromise his hideout in the next episode of the Flash that they have no idea what is about to begin.
What he was mentioning to them other than Savitar's debut could be the Dominators bringing a full scale invasion that Flash, Supergirl, Arrow, and the Legends of tomorrow are about to take on in the epic crossover starting at the end of this month which could be when Savitar will surface in the Arrowverse that throughout the Flash and Arrow episodes of the Invasion arc, Alchemy, his cult and maybe the Black Flash (Zoom who freed Savitar from wherever he was imprisoned in from the rest of reality) will help him regain his powers and maybe assemble a new army of super speedster ninjas for him to lead in his future confrontations with the Flash, and then probably in the Legends of Tomorrow episode of the Invasion arc, he and his ninjas may reveal themselves to Barry while the scarlet speedster himself and the other heroes are in the middle of their fight against the Dominators,
Savitar and his warriors will show up and slaughter all the remaining aliens that are invading Earth 1 with both their speed and swords in a way that heroes would not approve and if they do show up and get involved in fighting off the Dominators before attending to other matters, then this could be what Alchemy was preparing everyone for while restoring the powers to every individual that possessed them in Flashpoint and that the Dominators are probably what he was telling Joe, CCPD, and the Flash about in the promo to the next episode when he told them "You have no idea on what is about to begin", having Savitar and Flash meet for the first time during the upcoming epic crossover could be when he will appear in the Arrowverse very soon in before they become enemies later on and it would also give us more interesting backstory on why he in the Arrowverse would let his lust for power corrupt him just to get stronger and why he would be a threat to Barry and his team after he and his ninjas wipe out the last of the dominators.
And as for Alchemy, while the speculations of Tom Felton being the villain still stands, the expectation of his character Julian Albert, the one that works with Barry in the new timeline at the CCPD being Doctor Alchemy may need to decline by at least 30 to 40% until we discover for sure that Doctor Alchemy is him or perhaps, one of his dopplegangers from another world which would also support the theory that the Savitar Barry is about to face off with in season 3 could be from another earth as well because seeing how Julian started becoming a nice friend to Barry by letting him stay in the crime lab after Flash saved him from shooting a 15 year old kid by mistake which would have costed him everything for the rest of his life and he thanked the Flash for getting the kid behind the hologram monster charade out of the crossfire which helped earn eachother's trust and helped him admit that the reason he didn't trust Barry for over the past year was because he felt powerless which he referred to as the monster he was trying run away from and he was glad to go with Barry to get a drink before they both returned home for the night.So let's try to be careful on our speculation on Tom Felton's Julian Albert on Earth 1 being Doctor Alchemy and another good reason why is because of how Felton's character's last name "Albert" being the first name of Doctor Alchemy's true identity Albert Desmond, it would be another good explaination to why the Doctor Alchemy the Flash is dealing with in the third season may have come from another Earth as well since CW has put dopplegangers throughout the Multiverse into good use.
Now as Caitlin Snow in the third season of the Flash ended up posessing cryokinetic superpowers, she hasn't told Barry or anyone else on the team about them yet. No doubt that because of all the suffering Barry went through and how all that pain lead him into screwing with the timeline and how it all wasn't reset back to the way it exactly was after Eobard helped him restore it. Caitlin in the 50th episode of the series used her ice powers to free Barry from Mirror Master's mirror while no one was looking and later after showering in her apartment, she saw a piece of her hair had turned white which brings her into reuniting with the mother that abandoned her over her father's passing.
While Caitlin had confirmed that her powers have awakened over a few months ago and that they weren't developed from the particle excellorator explosions, chances are that other than Doctor Alchemy using his items to make her have powers like her Earth 2 doppleganger from Earth 2, that Zoom must have taken a sample of her doppleganger's DNA and injected it into Earth 1 Caitlin as he was willing to see her turn to the darkside like he did while he had her under his supervision after kidnapping her from the team. So clearly if that is so then all that Alchemy has done was excellerate the process of her metahuman genes as he is also tapping into her anger, making her lose control and soon, once he escapes police custody, he will then make Caitlin reach the full potential of her abilities further by tapping deeper into her rage will then drive her out of control.
As for how the episode of Caitlin Snow's transformation into Killer Frost should turn out; Caitlin as a heavily and traumatically enraged Killer Frost should at least succeed on killing at least 5 to 10 innocent adult civilians before Barry uses his speed to keep any of that from happening so that not only will this make the series better but because Barry agreed with Jay Garrick on the fact that he has to live with the mistakes he's made by not giving into his penance over them and the one way to make sure he doesn't succeed on keeping Caitlin from killing anyone in the upcoming potential Flash episode titled after the character is for her as Killer Frost to start lashing out at everyone with her cryokinetic powers and kills at least two to four officers before the aversive speedster and his team discover her secret or at least after she stabs Barry unaware in the gut with her icicles to immbolize him before doing so in the end of the upcoming episode "Shade" just before making her kills in Central City.
And for how the Flash's climatic confrontation with Killer Frost is to turn out; While Barry tries to convince Caitlin to fight off Alchemy's control she is to resist and keep attacking him and anyone nearby and accuses Barry for making her what she by not being as optimistic and aware of consequences during their war against Zoom in season 2 that he wouldn't stop worrying so much about the people being at the mercy of his arch enemy when bringing Zoom into their world led to bigger problems that were much worse than they were after escaping the hornet's nest. Worst things like Caitlin being kidnapped by Zoom that while he held her captive that he could have injected the genes of her doppleganger into her which is how she gets her powers and that with Alchemy making them develope faster than at normal rate, Hunter may have been in contact with him and more of his allies scattered throughout the multiverse during episodes 42 and 46 for help, along with Zoom killing a bunch of cops in a brutal act of terrorism just to remind Joe and the police captain that if they didn't have their men stand down from opposing him, he would kill more as well as having his army cause lots of destruction to the city, and because Barry refused to let the hunt for the Metas last longer than a week his decision on using Star Lab's multidimentional soundwaves to take most of them in range down is what angered Zoom into killing his father due to the fact that Barry is refusing to admit that they are the same because of the traumas they went through at the same age with the results of the incidents being the same, Caitlin would then turn her blame on Barry for Ronnie's death while she rampages through Central City for Doctor Alchemy.
Why? Because of how Barry kept on giving in to his fears and his penances throughout the series since stopping Weather Wizard from killing Joe for his brother's death, that he hesitated from saving his mother from getting killed when he was given permission by Eobard on his deal of the bargain to stop him that coming back to oppose him, along with his incapability to stop worrying so much about Zoom threatening all the innocent people on Earth 2 after getting Jesse safe and away from the meta terrorist leader, his lack of rethinking his decision of bringing Zoom into their world after sealing off the breaches to the rest of the multiverse to keep him from coming after them which is what led Barry into letting Zolomon abduct Wally for his speed and with Barry being retarded on not thinking clearly that even if he does give up his speed to Zoom in which he did, Zoom still won't stop terrorizing the multiverse, and that if Barry didn't hesitate from stopping Zoom from powering up the magnatar and that he should have just killed him after Zolomon murdered his father in front of him, even if it was just his remnant or before letting Zoom complete the final lap of powering the machine up as well as Barry lacking the stability to move pass his loss after seeing that Zoom's prisoner Jay Garrick was his father from Earth 3 made him trigger flashpoint and then with Eobard helping him reset it made him screw up everyone's lives over his lack of optimism and responsibility of handling the worst of consequences, having Caitlin as an enraged Killer Frost berate Barry for all those mistakes that his incapability to handling losses, sacrifices, casualties, wars, and violence made him wrought upon her and the rest of Earth 1 that if he would have learned to toughen up on his emotions and not let his mother's death make his worries over other people's lives so much consume him with fear, she would never ended up becoming what she is in now, that Ronnie would still be alive if Barry just saved his mother when traveling back to save her the first time she and his father would both still be alive today and if Barry doesn't acknowledge her sentence just by telling her to stop acting as the villain she is and doesn't answer why he couldn't embrace his fears and losses back in the 1st and 2nd season of the series.
And hopefully just as Killer Frost and Flash along with Vibe fight eachother in the final act of the episode she is to ask him these questions that she demands the right to know;
"Why is it that you couldn't handle the losses before traveling back in time?"
"Do you any idea what this 11 year old minded wimp has done to us Cisco?"
"He killed my husband and your brother with his unwise decisions because all he cares about is himself!"
"Why didn't you listen to Wells when he warned you that Zoom doesn't care about who he uses against you?"
"What is it that you couldn't stop worrying so much about Earth 2 when ignoring the people in danger after saving Jesse would have saved your father and Cisco's brother from ending up dead and that I wouldn't have ended up being taken by that monster just to keep him from killing you?"
"WHY CAN'T YOU TOUGHEN YOUR EMOTIONS UP AND STOP WORRYING TOO MUCH ABOUT OTHERS?!"
"WHY WON'T YOU ADMIT IT!?"
and hopefully Barry will explain why he couldn't handle all of the things he did that led to the catastrophes he went through in the first 2 seasons of the show with a more specific answer that that involves his mental stability and not because of what he feels is right or wrong
just like the Joker talking to Batman about how big a waste the world is by telling him that it's all a joke before Batman answers his question and irritates Joker by telling him that Gordon resisted giving in to the madness he tried to corrupt him with and then Barry is to get angry while explaining more on why he couldn't stop his fears over the years from making things worse and why it is he can't turn his back on being a hero now and to defeat the Killer Frost incase he and Cisco can't get her to settle down with words or with visions of their past and after all the damage she is about to cause, the Caitlin he was friends with over the past 2 seasons while making sure he brings her into custody alive for redemption, he is to carefully subdue her with his lightning, aerokinesis by hand or running around in a circle or by knocking her out cold (into unconciousness) with careful precision while charging at he at super speed straight on or by sideswiping her while making sure she doesn't crash into anything that she would easily die from any blunt force trauma or with the help of an old enemy that Barry fought who has gone through some of the same traumas that Caitlin went through regarding issues with her family and not being able to have a normal life who Jay will bring into Earth 1 to help team Flash apprehend Killer Frost before things get worse and she is played by the Robbie Amell's wife Italia Ricci Amell
Siobhan Smythe/Silver Banshee While this theory is 90% doubtful, 10% chances are that Kevin Smith and the crew may have been able to get Italia to reprise her role from Supergirl in this show's 53rd episode for a surprise appearance by having shot some scenes where Italia as the Silver Banshee arrives on the scene to give Barry and Cisco the chance to save Julian while she subdues Killer Frost with her sonic screams to immobolize her while shattering all the ice within their vicinity into dust and bringing down the icy house and Siobhan will make sure Caitlin is apprehended even if she has to punch her out into unconciousness before having the team lock their fallen friend into the pipeline until she is able to come to her senses. Even though Barry will be lucky to have saved Caitlin from letting her actions get herself killed by any of the CCPD officers, he will realize that she was right on the fact that he should have been able to move pass the trauma Eobard caused him and started toughening up his emotions before making the mistakes that made him screw up everyone's life. He and the rest of team will thank Jay and Siobhan for their help before Garrick brings her back to Earth 4 so she can have her sentence shorten and await her release from the metahuman prison Barry helped the officials build as a reformed person.
Of course just like Siobhan Smythe/Silver Banshee who is yet to return later in Supergirl season 2 where she is sure to put her difference with Kara aside and redeems herself from being a villain to becoming a hero once she finds out who the real person that caused her all the trouble that led her into becoming the rival to the girl of Steel in season 1, even if it's the Silver Banshee that Superman has fought before his cousin arrived on earth. Afterall it was confirmed by actress Italia Ricci that her character won't stay bad for long and the same is sure to be expected for actress Daniel Panabaker's character Caitlin Snow/Killer Frost is sure to be redeemed sometime soon since she dropped a slight spoiler on what CW has planned for her character after her face off with the Flash just by telling everyone how excited she is for the "three episode arc" Invasion arc. Still we can't be certain that her excitement for the crossover means that she will be involved in helping the heroes stopped the dominators since we know that because of how dark the episode of her becoming Killer Frost and betrayal to Barry and the rest of the team will be and even though Barry was able to help Frankie Kane keep Alchemy from letting the Flashpoint version of herself take her over and cause incidents that she would have regreted for the rest of her life, not everyone gets that lucky the second time. So when Caitlin turns to the dark side as Killer Frost either by her own free will or with Alchemy tapping into her rage, she will hurt more than a few innocent people once she starts going berserk with her cryokinetic powers on Central City and since she lasted this long as a friend and ally of the Flash here in the Arrowverse, well, not everybody has a happy ending so once Killer Frost does start attacking people with her powers through hurt or murder Barry is gonna have to live with the consequence once she starts freezing her victims dead or alive, cop or innocent person and even though he is quick at saving people from being killed, we do know that just how potential this episode of his friends evolution into Killer Frost really is, he is definately not gonna succeed saving everyone from ending up frozen or killed by Killer Frost because other than her ice powers under 0 degrees are cold enough to make the Flash's speed slower, his attempts to convince Caitlin to fight off Alchemy's control over her mind will distract him keeping everyone in the city along with their friends, families and people close to them from ending up caught in her icy crosshairs. So even though Panabaker will still be here in the show after she and Grant face off against eachother, we do know that despite her character being scared or under Alchemy's pathokinetic influence, the results from her rampage are not going to end well for her after Barry subdues her because unlike Siobhan Smythe from Supergirl who despite being imprisoned by Barry for her actions as the Silver Banshee was lucky that she didn't kill anyone or hurt and threatened so many people like Livewire has, Caitlin's actions are sure to be worse as we know that her actions of antagonizing Barry will certainly not go unanswered and even if Vibe helps him subdue the villain, you can't expect him to bring her back from the dark side soon because other than how lame it would be to rush the process of her rehibilitation, its primarily because.... Barry won't learn the hard way to not let his emotions ever get in the way of thinking about the consequences ever again like last season.
Even if it's Cecile Horton the woman that Joe starts falling in love with it's one sacrifice that CW will need to make to have the plot of this upcoming episode show a strong point of view, that no matter how hard people try to keep the situation contained and just when things start going your way, things will still get worse no matter what you do to prevent them from happening.
Well while we are still waiting for that episode to come in the next few weeks this month and await our chances to vote on this year's presidential election, we can compare the difference between Siobhan Smythe and Caitlin Snow on each of their stability when turning to the dark side and if Savitar will make his debut in the end of the episode Killer Frost and his big comeback into reality along with a new army of super speedster ninjas in the climatic battle of the third episode to the Invasion crossover in Legends of Tomorrow. In the meantime, be ready for next week's new episode of the Flash where Wally meets Alchemy and Barry deals with the Shade.