The following contains spoilers for Batman #126, on sale now from DC Comics.
Batman is prepared for every eventuality. He's built up a major reputation around that fact. When fans are debating who Batman can beat in a fight, they'll often ask if the Dark Knight has prep time. The reason for that, of course, is because if Batman has time to prepare then he can beat even the most impossible of odds. Unfortunately, this hyper-preparedness isn't always a good thing and the current threat the Dark Knight is facing has highlighted just how dangerous it could be.
Batman #126 (by Chip Zdarsky, Jorge Jiménez, Tomeu Morey, and VC's Clayton Cowles) saw the hero face his latest threat, Failsafe. From the looks of things, this new enemy is something that Batman created himself, as a failsafe in case something happened to him. Strangely though, he doesn't remember Failsafe at all - despite being able to remember everything. That's when he called on another hidden failsafe he created, which suggests a dangerous possibility.
This issue alluded to the possibility that the Dark Knight's backup personality, the Batman of Zur-En-Arrh, may have been responsible for creating Failsafe. If that's the case, it shows that the Dark Knight's ultra-cautious nature may be more out of control than initially thought. There have been multiple instances where Batman has created fail-safes against disasters that have gone horribly wrong. The iconic Tower of Babel story is the most well-known. The Dark Knight created plans that could be used to kill every single member of the Justice League if they ever went rogue.
Those plans fell into the hands of Ra's al Ghul and were used to take out the entire League. If that incident wasn't bad enough, Batman created Brother Eye to keep an eye on the Earth's metahuman population. The system was hijacked and used for far more nefarious means - as it began to target the planets metahumans and Wonder Woman's home of Themyscira. All of this shows that Batman's fail-safes can be used for evil.
Even just knowing about them isn't enough to counteract them. That's why Failsafe and the Batman of Zur-En-Arrh are so troubling. Batman at least knew about Brother Eye and the stolen plans from Tower of Babel. He won't have any knowledge of the fail-safes created by the Batman of Zur-En-Arrh. Who knows how many other contingencies like Failsafe there are out there? All created by the mind of the Dark Knight himself but completely unknown to him.
This revelation in the pages of Batman #126 could suggest that there is any number of fail-safes on the scale of Brother Eye and Tower of Babel out there, which absolutely no one knows about them - not even Batman. Failsafe came out of nowhere and now there's the possibility that there's something worse somewhere. Failsafe has been described as Batman's Doomsday. What could be worse than Doomsday? On top of all that, who's to say there aren't even more backup personalities in the Dark Knight's mind? The Batman of Zur-En-Arrh was created in case Bruce Wayne suffered from some form of mental attack.
What if that backup Batman prepared for the same eventuality? He could have created another, even more aggressive personality as a defense if he too fell victim to a psychological assault. Perhaps that personality would be willing to break Batman's no-kill rule. The alternate Batman we've seen is already unhinged, the idea of there being more lurking around in the depths of Bruce's mind that are somehow worse scarcely bares thinking about.
This current storyline is suggesting some dangerous things about the Dark Knight. Failsafe and Batman Zur-En-Arrh feel like warnings. They're just the tip of the iceberg and there are more out there like them. Fail-safes that are dangerous and deadly, with consequences that could be devastating for the DC Universe. Fail-safes that no one knows about. Not even the person that created them.