I cast living death when opponent has Imposing Sovereign in graveyard do my creatures come into play untap or tapped. This is a confusing interaction and not sure the correct answer. I have gotten multiple answers for Yes and NO.

Every creature enters the battlefield untapped.

Imposing Sovereign has a replacement effect that affects a generic group of objects; it has to exist before creatures enter the battlefield in order to apply to them. With Living Death all creatures enter the battlefield at the same time so the effect can't apply to them. Because it affects a generic group of objects, it also won't affect Imposing Sovereign itself.

This and much more about entering the battlefield is covered in this article: http://blogs.magicjudges.org/articles/2013/12/31/enter-the-arena/

Daniel Kitachewsky
L3, Paris, France
Rules NetRep