And after Alchemy lost his Philosopher’s Stone, he warned of bad things coming, and that’s when everything went haywire as Joe’s officers started getting taken out left and right by an “invisible” source that, of course, turned out to be Savitar.
For a refresher: as the climax for “Shade” was underway, Wally was baiting Doctor Alchemy while Joe, Flash and others were waiting to take the dream-distorting antagonist down.
The new villain puts Barry in a precarious position – which makes it seem like he’s got some mass to him – and mentions that whole “god of speed” thing, which ties back to his comic origins.