When does Pride appear in Fullmetal Alchemist Brotherhood?

Pride, the final Homunculus, doesn't appear until Episode 48, titled "The Truth". He's introduced as a mysterious figure who watches over the events unfolding in Amestris, and his true identity is revealed gradually throughout the series.

However, you can get a sense of his presence much earlier. His influence is felt throughout the series, particularly in the actions of Father and the other Homunculi.

For a complete understanding of Pride's character and role, you'll need to watch the series in its entirety.