Dabi reveal his identity infront of you, Endeavour and Shoto, Naming himself ‘Touya’ like the eldest son of Endeavour. And big brother of Shoto.

While he was dancing on the big thing called Machia he explained his backstory to taunt Shoto and Endeavour. As he said for Endeavour to come dance with him in hell, while he danced like a madman, both Endeavour and Shoto were traumatised, this war was worse than expected.