User blog comment:Zeref Fullbuster/Dabi is Shoto's eldest brother Toya/@comment-4641958-20191001101406/@comment-40183640-20191015004225

All the other theories, suck or are too broad. Hopefully, the anime only will realize how irrelevant the U.A Traitor is. The Dabi Todoroki theory is the only interesting one tbh