I roll the 4 plus after killing a unit so I can summon a Which summoner and which card's effects are you referring to?
Conjuration onto the spot I killed the unit and that unit was a shadow.
Question is where does my opponent put Thier shadow unit if they chose to and had one in Thier hand to place cause now my Conjuration is in the place where Thier card says they can put Thier unit?
EDIT: I assume you mean Harbinger from Immortal Elien deck vs Shadow from Melundak deck.
Here is the answer: Fallen Phoenix Harbinger and Jungle Shadow Shadow Interaction
And if that's the case then you have posted your question in wrong forum.