Title says it all, under Satan and would help with exposure of a target’s dirty laundry.
every demon that causes disaster orbis comes to mind
Lucifer for the win! He absolutely positively hates lying and will expose it at all costs.
Also, King Paimon, He can’t abide a liar. Plus, King Paimon has exposed people who are liars to me all the time. He tends to really enjoy exposing the ones who think they are super slick.
Also, if you want to know who your true friends are—King Paimon will show you who is your true friend and definitely who is NOT your friend. What He will show you isn’t always what you’d like to see, but if you need to see the truth, ask Him.
Belial would also be a great choice in this predicament.