Can I just—
Erwin must’ve been watching Levi for a LONG time. Levi’s the only one he wants and when they split, only Mike and Erwin went after Levi while the two others went after Farlan and Isabel separately instead of all 4 going after Levi:
Erwin already knew how to get to him -threaten his friends. Their crimes in the Underground isn’t a matter of Scouting Legion business. Erwin had to know exactly what crimes they committed and how severe their punishment would be for his threat to have had any weight. Erwin didn’t need Farlan and Isabel, he clearly had no interested in them. But he sent two of his after them because threatening that the two were never going to see the light of day again was how to get Levi to pay attention to anything he had to say.
Even for thugs in the Underground where it seems like it’s every man for himself, Erwin knew Levi wasn’t going to hang his entourage out to dry.
Just how long had he been watching Levi? Commander Stalker.