Is the bug in the black temple the final boss?

[Shiro Tamashi]

I went into the temple after opening it and haven't fought him yet since i don't want the game to end. If he isn't the final boss then i'll fight him and progress forward. Currently stuck at Nightmare King - I suck at dodging his bullet hell. Wanted to see if i could explore past that boss in black temple to upgrade my weapon or get some good charms to help with Grimm.

[Darc Vader]

Technically yes, but you should still do it now if you care about achievements. The game will let you continue to play afterwards, and there is stuff you can do to expand on the ending which will lock you out of getting the basic end(and related achievement) once you do it.

[Boksha]

Originally posted by Darc Vader:

Technically yes, but you should still do it now

^ This, basically. Finishing the game doesn't overwrite your save, so you can beat the game as often as you want without losing your progress.

[Darc Vader]

Also for the record, Nightmare King Grimm is one of those post-game superbosses, so if you don’t have all the upgrades you might want to leave him until later on.

[River Victor]

The guy in the Black Egg Temple is the final boss, technically. How you kill him changes the ending. So if you can kill him as soon as you can, you should try right away. That's the first ending. The steps to get the second ending is irreversible and starts after you get the charm at the lower right corner on your charm list. Once you do, if you have no backup save, you can never get the first ending on the same playthrough again.

[Shiro Tamashi]

Thanks guys! I was afraid of getting kicked into NG+ mode like Dark Souls. I heard about the bad ending and good ending, currently I have the half white charm of the lower right corner of my charm inventory. So I'm assuming I won't get locked out right now since it's incomplete.