"Her heart is a crater, and we have filled it" The name of the new artifact we get in Battle for azeroth is called the heart of azeroth.
"Its surface blazes bright, masking shadows below" A new mineral called Azerite has started to pop up on the surface of azeroth, it apparently glows bright with power.
"The king of diamonds has been made a pawn" Magni, the king of diamonds. Is the one who gives us the necklace.

We infuse our new artifacts with azerite, filling it with power. The old gods power.