Since EDH is a mostly casual format and its not played in matches of more than one game there arent really any rules about sideboards
The Assassin is a Dimir flashable 3/3 that enters the battlefield tapped as a Clone of any dork and then can destroy it like an six-mana Ravenous Chupacabra that leaves behind a tapped Clone of that dork you just killed and can serve as a Clone of your key dork instead if that is how the battlefield plays out
Opalescence is clearly an enchantment deck build-around, which let you turn Replenish into not only a source of lots of virtual card advantage, but also a massive battlefield position that could easily dominate and end the game
Black gets glances as part of certain discard spells where it needs to see the hand, such as Duress or Coercion, to make choices of what gets discarded
I had to put aside my insecurities about being a beginner to reveal my true connection to the practice
While Delver decks average seventeen lands, those that have one Quicksand tend to have a second (and also tend to average nineteen lands)