Batman: Arkham Origins
49 Achievements
80-100h
Perhaps sooner, Perhaps later
Defeat the Joker Details for this achievement will be revealed once unlocked
34.1%
How to unlock the Perhaps sooner, Perhaps later achievement in Batman: Arkham Origins - Definitive Guide
As pointed out by GodLike499, you cannot return to free roam once you enter the door to the bridge and begin the fight with Firefly. You must complete these missions before you are able to continue with other side missions and achievements.
Story Related and cannot be missed. This is unlocked after completing the game.
The main threat here isn't the Joker, but the previous fights with Bane. For the first phase of the fight, use the same methods outlined in the One Rule trophy. Eventually a cutscene will play, Bane will inject himself with more Titan, massively inflating him and Batman will destroy the floor. Then you'll be in a little cat and mouse battle with him, and you'll need to get to where he can't see you and take him down to take down his health. After this you'll continue on to a few more enemies then to a cathedral where you will find the Joker. This is extremely simple, you just need to hit him a couple of times then it will go into a beatdown section, ending the game. This will unlock in the final cutscene.
Story related, cannot be missed.
This achievement will unlock after subduing The Joker inside Blackgate Prison's chapel.