With armageddon approaching, a museum security guard with a background in psychology must destroy the Egyptian god of chaos, who is disguising himself as various museum employees while committing a grisly string of murders.

Hi there – personally, I actually preferred some of the earlier attempts of this logline, where the focus was on the mysterious murders/deaths, the artifact, and the security guards role in trying to solve the mystery and save himself.

When the logline opens “With armageddon approaching…” it loses me. It either means (a) armageddon is coming regardless, in which case the rest of the logline is pretty inconsequential; or (b) something in the story is *potentially bringing* armageddon – this seems a better option, but then that needs to be indicated, rather than starting with ‘armageddon is coming’.

It also feels to me you have too many elements,a nd its not clear what the focus is. We have (a) armageddon (b) security guard (c) psychology background (d) egyptian god of chaos (e) disguising as museum employees (f) murders…..and this is *without* any mention of the key item in the title – the artifact!

Here is a suggestion from the above, but still seems too busy…
“When a museum security guard uncovers the link between an ancient artifact and a string of murders, his investigations lead him to the Egyptian god of chaos and a battle where the future of the world is at stake.”

Not sure that has hit the spot, but good luck!