Even though it was a very minute fluctuation in his expressions, the Left Guardian noticed it. She looked particularly interested in Eren, but she didn't say anything to him.
If the second possibility was true and the person was able to disguise, it meant the killer might be here. It could be Ruby, or Eren. It might have already killed one of them and taken their position.
She could verify her assumption right here, but she didn't want to give that person any chance to escape. It was better to be sure, than to risk it. Even if it was her, she didn't know the extent of abilities the killer had.
If he could assassinate Treniel who was more cautious, then he couldn't be a fool. If it was indeed Eren or Ruby, then it was never too late to verify after reaching the Necromancer Tower.
She raised her finger, her shadow growing bigger until it was covering the entire estate area. From her shadows, many Undeads started crawling out.
