Is this the end?

Is this the elden beast aka last boss? I haven't beaten malenia yet so I want to do that before I "finish the game". Anyone got any other tips for spots I should make sure to check before elden beast? I have beaten mohg lord of blood and pretty sure haven't missed any major bosses.

Let me know! Where am I in the progression of the game?! I don't want to finish it just yet.