Backstory: Elspeth is from some unknown plane of phyrexians, perhaps even Phyrexia itself. She spent her youth being tortured at the pleasure of its inhabitants, before her spark ignited at a very young age and she planeswalked to Theros, then traveled multiple planes until she eventually calling Bant home. She's always had haunting dreams of her youth (although there seems to be a bit more going on with that in this story).

The creature torturing her looks like either a Negator or Obliterator, although their popularity has lent their aesthetics to more cards.

The card itself is interesting. If it hits a creature when it enters, it's pure upside from there.. But.. The opponent has a turn to see the discard coming, so the chances of hitting something good on the second counter is diminished.

The spear in this has a single jewel, so I guess Ashiok merges this one from her nightmare and Godsend (or her mask) to make Shadowspear (aka "God's End")?

That brings up a lot of things to retcon, though. (Like, how could a post-Mending 'walker be from a plane full of Phyrexians other than New Phyrexia? Which, one, she's not from, and two, she got to witness its transformation. And even New Phyrexia, Karn was unconsciously working to make a home for his "children".)