WARNING: The following article contains SPOILERS for the Arrow Episode "The Thanatos Guild"
"The Thanatos Guild" has seen the departure of one of the few remaining original cast members of Arrow, in a move that should herald the beginning of the end for the long-running superhero series. The show has not yet been confirmed for a seventh season by The CW, but the shows' writers have apparently been working on scripts for it since August of 2017.
"The Thanatos Guild" was built around a new League of Assassins, which had secretly been established by Malcolm Merlyn before his death on Lian Yu in the fifth season finale of Arrow. The so-called Guild sought out Thea Queen, Malcolm's daughter, believing her to either have the map to some great treasure that Merlyn had hidden or knowledge of how to find it. They were wrong on both counts, but their attempts to capture her aroused Thea's interest and delayed her plans to leave Star City with long-time love-interest Roy Harper.
With the assistance of Felicity Smoak and Nyssa Al Ghul (who has devoted herself to destroying all of her father's legacies including any attempts to revive The League of Assassins) Thea was able to locate the map and determined what her father's hidden treasure was - three Lazarus Pits undetected by Ra's Al Ghul during his time leading The League of Assassins. The episode concluded with Thea deciding that she would go with Nyssa to destroy the rest of The Lazarus Pits and Roy Harper going with them.
The departure of Thea Queen has apparently been in the works for some time. Willa Holland, who plays Thea, has apparently been wishing to leave Arrow since season 4. The producers did decrease her episode commitment in season 5, having Thea give up vigilantism for an office job as part of her brother's mayoral staff, after Oliver Queen (Stephen Amell) was elected Mayor of Star City in the season 4 finale. It was here that Thea adopted Deputy Mayor Quentin Lance (Paul Blackthorne) as something of a foster father, caring for him as he relapsed into alcoholism following the death of his daughter, Laurel. She was in a coma for the first part of season 6, having been caught in an explosion in the Season 6 opener.
Holland's departure was well-handled but it only served to emphasize how bloated the cast of Arrow has become over its six seasons. More, it showed how most of the main cast have reached points in their lives where there is very little personal drama for them outside their lives of superheroes and that most of them could live happily ever after. Indeed, one of the key complaints about season 6 has been that the writers seem to have been contriving conflicts between the core cast in order to add drama where there shouldn't be any.
Chief among these complaints have been Quentin Lance's sudden reversal regarding Black Siren (Katie Cassidy) - an unrepentant evil metahuman version of his daughter from a parallel Earth, whom Quentin suddenly became convinced could be persuaded to become good. Fans have also complained about the wedge driven between the Original Team Arrow (Oliver Queen, John Diggle and Felicity Smoak) and the new additions to the team (Dinah Drake, Rene Ramirez and Curtis Holt), which has resulted in Star City's heroes fighting each other more than the villains striving to take over their town.
This petty drama is nonsensical and it would really be better if Arrow were to start winding things down starting with Thea's departure. Let Oliver and Felicity settle down. Have Diggle focus on his wife and son instead of replacing Oliver as Green Arrow. Send Dinah to join the crew of The Waverider on Legends of Tomorrow. Have Rene run off with a cute physical therapist. Get Curtis to retire from superheroics and settle down with that nice cop he started dating. Bring Sara Lance back in the finale, have her give Black Siren the beating she's had coming and let her remind Quentin that he still has a great daughter who loves him. Let Arrow end happily, if not strongly.