What is inside the Gate of Truth?


In FMA and FMA: Brotherhood, the Gate of Truth is shown to have an eye and a
bunch of arms inside of it. The arms drag people into the gate during human
transformation. I know that the creature sitting in front of the Gate is
Truth, but what is inside of the gate (i.e. the arms and the eye)?




In the manga and _Brotherhood_ , there are two things within the Gate of
Truth: God, and all alchemical knowledge that has ever existed or will ever
exist. The [_Fullmetal Alchemist_ Wiki](http://fma.wikia.com/wiki/The_Gate)
says it best:

> It is the source of alchemical knowledge and the entrance to God's domain,
> where no mortals are meant to tread.

As is stated in [this answer](https://anime.stackexchange.com/a/3209/274),
this is where mortals end up when they attempt human transmutation. They pay a
toll, and are granted access to all alchemical knowledge within.

!["It was as though all of the information in the world was shoved directly
into my head."](https://i.stack.imgur.com/W9CbW.png)

While an alchemist is within this realm (the realm of non-reality), they will
inevitably learn something about alchemy, and in fact anyone in the series who
recalls this information gains the ability to perform transmutation without a
circle.

In the 2003 anime, there are some differences. Notably, the realm itself is
the source of alchemical energy (rather than knowledge), and the Gate acts as
a portal between that energy and the _FMA_ universe. You can read more about
the differences on [the _FMA_
Wiki](http://fma.wikia.com/wiki/The_Gate#In_the_2003_Anime).




In the manga and _Brotherhood_ , there are two things within the Gate of
Truth: God, and all alchemical knowledge that has ever existed or will ever
exist. The [_Fullmetal Alchemist_ Wiki](http://fma.wikia.com/wiki/The_Gate)
says it best:

> It is the source of alchemical knowledge and the entrance to God's domain,
> where no mortals are meant to tread.

As is stated in [this answer](https://anime.stackexchange.com/a/3209/274),
this is where mortals end up when they attempt human transmutation. They pay a
toll, and are granted access to all alchemical knowledge within.

!["It was as though all of the information in the world was shoved directly
into my head."](https://i.stack.imgur.com/W9CbW.png)

While an alchemist is within this realm (the realm of non-reality), they will
inevitably learn something about alchemy, and in fact anyone in the series who
recalls this information gains the ability to perform transmutation without a
circle.

In the 2003 anime, there are some differences. Notably, the realm itself is
the source of alchemical energy (rather than knowledge), and the Gate acts as
a portal between that energy and the _FMA_ universe. You can read more about
the differences on [the _FMA_
Wiki](http://fma.wikia.com/wiki/The_Gate#In_the_2003_Anime).

