The Cultists
"The logic behind your action on the female ranker seems sound. But why did you amputate the other guy?"
'To vent out my frustration of having to talk with you.'
Eren answered Ken's next question inwardly. But what he spoke out loud was entirely different than his inner monologue:
"I did that so we would get to catch these enemies and interrogate them. Haven't you realised this part of our mission here?
If I'm not wrong, then Master Marla was trailing us from a distance because she wanted these guys to attack us. That means they've been doing this for a while now.
If Adapt Marla was with us, then this E-Ranker would have never dared to come out in the open. We were acting as baits to draw these sharks out.
There can only be one reason for this set-up to have been arranged. Adapt Marla wanted to catch these criminals and take them as prisoners to interrogate them.