Planned. As you can glean from all my stories, I write in a scene style, more like episodic tv. I jot that down in bits/scenes, in a big 'seed file' as I call it, then weave it together while I pick and choose from scenes. The one I didn't have was Callum, when I began the story. I knew I wanted Megan, as background noise but needed a counter to it. Then, when I wrote the scene with Kai and Doc, their first actual meet, Doc wrote himself, really. The pregnancy wasn't there either, it's just a 'vehicle' for them to have their scenes in the background.