'Arrow': SPOILER Leaves in "The Thanatos Guild"

Arrow returned from a brief hiatus tonight -- only for one character to bid the show farewell.

Spoilers for tonight's episode of Arrow, "The Thanatos Guild", below!

The episode saw Team Arrow dealing with a new threat, which was introduced by an ominous warning from Nyssa al Ghul (Katrina Law). As she explained, Malcolm Merlyn (John Barrowman) had formed a rogue band of League of Assassins members in the months before his death which became known as the Thanatos Guild.

The leader of that group, Athena (Kyra Zagorsky), had traveled to Star City in search of Thea Queen (Willa Holland). As it turns out, Malcolm was the owner of a map that led to some sort of ancient treasure, and the Thanatos Guild believed that Thea would be able to help unlock it.

This proved to be quite a problem for Thea, who had decided to follow through with the suggestion that Oliver Queen/Green Arrow (Stephen Amell) had made in the previous episode: that she and Roy Harper (Colton Haynes) leave Star City and try to make a better life for themselves. She and Roy reluctantly decided to help solve the problem with the Thanatos Guild, tracking down the map, and ultimately figuring out that it led to the existence of three new Lazarus Pits.

This excursion made Thea realize that she didn't want to end her vigilante days just yet, and that she would follow Nyssa to track down the remaining pits. Roy agreed to travel along, and the trio departed together.

In a way, some Arrow fans had seen this coming, considering the arc that Thea has undergone over the past few years. Over the past two seasons, Thea has taken on a significantly smaller role in Arrow's proceedings, allowing Holland to still appear here and there without killing Thea off of the show. For some, the one-two punch of Roy's return -- and the fact that Thea suited up again as Speedy in the past two episodes -- seemed to indicate an easy opportunity for Thea to make her exit.

"We love Willa, we love Thea the character and we particularly love Thea's relationship with Oliver," Guggenheim said back in 2017. "That said, Willa came to us at the end of season four and she, very honestly, expressed a desire to cut back how many episodes a season she was doing. She's a member of our family, and we wanted to honor that request. That's what happens when you have a show that goes over a hundred episodes, people start to say, 'Hey, I would like to pull back,' some people don't want to renew their contract. There's a whole host of different things that start to come into play and you work that into the story telling."

So, while Thea might be absent from Star City for the foreseeable future, fans will surely be curious to see if and when she eventually returns.

Arrow airs Thursdays at 9/8c on The CW.