Because Doctor Strange is in the MCU, and because the good Doctor himself will be showing up during the Infinity War two-parter, and because we need to get all those Infinity Stones out in the open before the movie hits or it’ll just be a mess of confusion right out the gate, Doctor Strange needed to introduce the Time Stone. But apparently, according to director Scott Derrickson, the Time Stone didn’t actually figure into the plot of the movie at all until very late in the drafting process.

Derrickson talked to about how the Stone’s origin in the movie was more of an organic process. It’s not even referred to by its actual name until the very end of the movie (the first time any of the Stones have been referred to in this way).

The last scene with Wong was shot after principal photography, when we decided to put that on as kind of the final scene. It was only then that we were looking for a way to tie it into the MCU.

Sounds pretty last-minute for a movie that’s supposed to introduce an integral component to the next ensemble film. Originally, it wasn’t even in the movie at all.

Well, that was definitely something that emerged throughout the creative process all the way through production and even more into editorial. We didn’t start out with the idea of time or even the time stone and move forward. It just continued to present itself as an important thematic notion.

He also discussed how the Time Stone seemed like a natural addition to the story, considering the whole thing was about the concept of time and how the protagonists either fight it or use it.

I knew from the first draft that Kaecilius’s desire to not die, to live essentially forever, was paramount to the story, but that was to me more of a religious notion than the physics of time itself. As we got more into the multiverse, multiple dimensions and all of that, the idea of time being a separate dimension itself, and Dormammu existing beyond time just sort of filtered it’s way into Strange’s story.

You get the watch and Christine saying, ‘Time will tell how much I love you,’ and the simple idea that if you’re going to be so bold as to create a character who’s confronting the question what is the meaning of my life, who am I in this vast multiverse … He is confronting that question as a creature of time.

To add such an important thing into a movie kinda sorta at the last minute is a little weird, but it’s also cool to hear how it all seemed to happen on its own. With Doctor Strange, we finally have all five Infinity Stones officially introduced into the MCU, and it’s only a matter of time before Thanos gets his gauntleted hand on them.