Doom (1993) was created by John Carmack and John Romero.
JC and JR.

Doom means judgment.

https://www.etymonline.com/word/doom
>from Old English dom "a law, statute, decree; administration of justice, judgment; justice, equity, righteousness,"
>Crack of doom is the last trump, the signal for the dissolution of all things.

The phrase "crack of doom" comes from Macbeth.
It's a reference to Judgment Day at the end of time.

https://www.folger.edu/explore/shakespeares-works/macbeth/read/4/1/
>What, will the line stretch out to th’ crack of doom?

Lord of the Rings is about a journey to the Crack of Doom.
It's a hellish abyss.