Its nice as a control draw-go finisher, and you can cast it when they fetch a land, tutor a card, and more
You can find full details on Card Conduit's FAQ page
If your opponent controls a card, you can activate this card from your hand when a card or effect is activated that includes a Special Summon: you negate that effect, and if you have a Trap in your Graveyard, you destroy that card
The Shadow Realm itself was essentially added to the anime as a way to censor character deaths or severe injuries
Its such a bizarre card, since if your opponent has more life points than you, all they need to do is refuse that handshake
However, it's not our purview to discuss markups