Where was Garruk? Why in the world wasn't Garruk in War of the Spark? There are two answers to this question, one real world–based and one in-story. I'll start with the former. Garruk is a popular character, and we have a story we want to tell with him. Magic has a lot of Planeswalkers, and we're trying to balance giving as many as we can some time in the spotlight. That does mean some characters have to wait for their turn. The storyline we want to tell with Garruk just didn't line up with the Bolas Arc. For a while, Garruk showed up in Dominaria, but the way we had to twist things to make that work just didn't let us tell the Garruk story we want to tell. As I've said before, we have plans for Garruk, and you all will see him again. War of the Spark just wasn't the right fit.
In-story, Bolas's plan was to lure as many Planeswalkers to Ravnica as possible so that his Dreadhorde army could harvest their Sparks (incidentally killing them, but that wasn't Bolas's primary concern). Garruk is a very efficient Planeswalker hunter. The last thing Bolas wanted was to gather all these Planeswalkers in one place and then have Garruk slaughter a bunch of them before he could harvest their Sparks. That means, as Bolas was doing all his plotting to make sure as many Planeswalkers came to Ravnica as possible, he also had to spend some energy specifically making sure Garruk didn't show up.
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