Like the mental trick with dealing with Millstone, just imagine that the exiled cards are on the bottom of your library and dont sweat it (unless your deck plans on winning with a specific combination of cards)
It was released in 1999, so its old, historic in Pokemon terms, and its a very nice image
Anyway, while were talking about Underworld Breach: 1
Not quite a legendary, this mythical little buddy is said to grant victories to any trainer that manages to get cozy with it
though, Wall of Shards forces you to let your opponents gain life: one on your first upkeep, two on your second, and so on
It will add an interesting dynamic, especially if paired with the Unstoppable Slasher and Bloodletter of Aclazotz combo