I heard that major events of Tactics are canon but things like Vault 0 seem unlikely given the nature of vaults and that there is a BOS that has ghouls, intelligent hairy death claws, and super mutants in it's ranks. I'm a little confused about it.

The "high events", basically there was a splinter group of the Brotherhood who became the Midwestern Brotherhood of Steel and they did fight the Calculator and its robotic army. Until Bethesda actually elaborates on whatever details they consider canon, it's best to only acknowledge those two broad aspects of the storyline.


How so?


The Midwestern Brotherhood leaders have completely different beliefs in regards to recruiting, which is if I remember correctly the largest contributing factor behind their exile.

Bethesda has said the "high level events" of Tactics are canon. And the existance of the MWBOS has been 100% confirmed.

What exactly the "high level events are" is yet to be determined, but almost certainly includes the calculator.


The entire story behind the MWBOS is that they were (essentially) exiled for their rather radical ways of doing things which the traditional elders disapproved of.

The MWBOS also varies widely depending on the ending to Tactics. If the Barnaky ending is canon, the MWBOS becomes a anti-mutant dictatorship.