Step 1: The existence of Water dude. Water dude tells us what the monster of the week’s powers are. Except we didn’t get that for anyone before Yuu joined the Council.
Step 2: Nao and speed dude, did though. They probably got a single word, something which isn’t very explanatory. Nao however is freaking good at this shizz, whilst speed dude is more reserved.
Step 3: Nao has repeatedly shown a large interest in Yuu’s power. Baseball segment, plus her denying of him using it on Speed dude in ep 6. To elaborate on the previous point, she freaking kicked him out a window. What could Yuu have done that wasn’t as bad as that? Therefore the issue wasn’t that Yuu was gonna do something bad to him, but that he was going to use his power.
Step 4: Yuu’s identity issues fit in with his power, cool. But even if his power isn’t ‘control person for 5s’ that doesn’t destroy how his issues can fit with his power. Not knowing his own power properly fits afterall.
Step 5: Water dude can detect where people with a power is and what there power is. He’s there at the end. The rock is overturned. He’s detecting someone who shouldn’t be there. Doesn’t in particular have to mean Yuu’s power isn’t what Yuu thinks it is, but Yuu’s power as described wouldn’t save him from that. Doesn’t mean he’s alive either I suppose, since we do have someone who can bring people back from the dead. But it works as a form of foreshadowing no matter what.
