Board Thread:Site Discussion/@comment-76.191.49.254-20170303160310/@comment-181.208.210.95-20170605191341

Well it's not Toga since the traitor has probably been around since the first arc to give away the position of where Class A would be training.

My belief is the usual one. I think it's Denki. There are a couple of problems with this one but there's also the most evidence.

In favor:

Denki's original design is that of a bad guy, he wasn't in the shot of the kids sleeping in the boot camp and we see an empty bed, he thinks Stain is cool and people believe that he's not giving it his all and just faking his limits, he wasn't hurt in the boot camp attack.

Against:

How could he know where he was heading in the USJ arc (my belief is that Kyoka overheard a conversation and casually mentioned it to Denki).

He looks genuinely worried for Midoriya after the Shigaraki.