Warning: spoilers ahead for the midseason finale of Arrow Season 6, "Irreconcilable Differences."
The first half of Season 6 of Arrow has been a wild ride for Oliver Queen and Team Arrow. Oliver gave up his position as the Green Arrow in order to focus on fatherhood and running Star City as mayor, but leaving the vigilante scene wasn't that simple. FBI Agent Samanda Watson came to Star City to investigate Oliver, believing him to be the Green Arrow. At the same time, Diggle was hiding degenerative nerve damage so he could continue to fight crime as the new Green Arrow. Vigilante's identity was revealed, Thea woke up from her latest coma, and Wild Dog wrote a speech. Everything finally came to a head in "Irreconcilable Differences" when a brand new supervillain threat emerged that could very well ruin everything the good guys have built for themselves in Star City.
The majority of "Irreconcilable Differences" revolved around Oliver's discovery that a member of Team Arrow had agreed to testify against him for Samanda Watson. The trio of the original Team Arrow put the other three under surveillance, but the truth ultimately came out when Wild Dog admitted that he was the one who betrayed Oliver because Watson had leverage on him. She could throw him in jail for his vigilante activities or reunite him with his daughter.
It really seemed like the midseason finale was going to be all about the importance of trust and teamwork, with the climax of the episode as the newbie members of Team Arrow decided they didn't trust Oliver enough to stick around. Instead, the big twist came in the final moments when we saw the most significant threat of Season 6 to date: a team of villains.
The episode ended with Cayden James and Black Siren -- who teamed up in a previous episode -- watching Oliver, Diggle, and Felicity over cameras Black Siren had planted in the Arrow bunker months previously. They were joined by Bratva bigwig Anatoly Knyazev, wild card killer Vigilante (who claims to be on Dinah's side), and Richard Dragon, and it was clear that they were all very much in cahoots. Now, each one of these baddies is dangerous in their own way, and Team Arrow has had a difficult time with many of them. These five villains united in a purpose could be nigh on unstoppable for Team Arrow, especially now that Team Arrow consists only of Oliver, Diggle and Felicity.
Admittedly, Oliver, Diggle, and Felicity were perfectly capable of handling the vigilante scene on their own in earlier seasons, but Season 6 has been complicated for all of them. Diggle hasn't entirely recuperated from his nerve damage, Oliver is being investigated and really should risk being seen on the streets, and Felicity has to try and figure out ways for everybody to survive. Original Team Arrow in their current state may not be able to handle all these villains, although it could be fun to at least watch them in sync with each other again without any newbies in the mix.
What makes this new team-up of bad guys so very dangerous has to be that they all have different motives and probably different endgames in mind. Sure, they're probably united behind a drive to get rid of the Green Arrow and do a lot of damage, but we can bet that Dragon's vision for Star City is very different from Anatoly's, and Cayden James is difficult to predict. Black Siren has been more or less content to watch the world burn if she gets to help light the fires, although she did finally show some sympathy to Quentin in the midseason finale. Vigilante is very personal to Dinah, and she already struggled to take him out.
Basically, what seems to be the Arrow version of the Legion of Doom has most of the advantages moving forward. With Team Arrow down to three members, the bad guys have the numbers. They also don't impose the same kinds of limits on themselves that the heroes do, and we can bet that they won't show the same kind of mercies. They'll have different motivations, different talents, and different weapons. Oliver and Co. are in a lot of trouble, and Samanda Watson still must be a factor in his life somehow. The bad guys have already managed to set events in motion that broke Team Arrow in half; who knows what they have in store next?
Arrow will return to the airwaves for the second half of Season 6 in 2018. Take a look at our midseason TV premiere guide for the dates you'll need in the new year, and be sure to swing by our breakdown of why the Arrow-verse shows need to cut their episode orders.