To be honest, other than the Witch's Legacy, Kieran couldn't think of anything else that could drive Broker into doing what he did.
Or perhaps it was his original plan all along?
The title dungeon and the Witch's Legacy, Broker had no intention to give up on either one.
As for how Broker could get his hands on information regarding the [Blade of the Daybreaker (Sub Scroll)] and the Witch's Legacy at the same time?
Kieran never doubted the capabilities of a Unique Title player.
Moreover, the existence of the secret bazaar and the other properties had stated how influential Broker was.
Kieran rearranged his thoughts; he told every single one of his speculations to Lawless and Starbeck without further concealing anything.
Lawless was his best friend in the game, so there was no need to hide it.
I wouldn't say I change the time so that I can get 1st :)