Abysscraft is the merger of what was formerly Bloodcraft and Shadowcraft. Although elements of both decks remain, it's not quite the same. From the Blood side, we retain the class identity of utilising cards that take a chunk out of own leader's health in order to powerful cards that could otherwise not be balanced at their play point range. From the Shadow side of things, Worlds Beyond maintains the Shadow/Necromancy mechanic and Reanimate. Shadows refer to the number of cards within your Cemetery. These can be expended via cards with the Necromancy tag, enhancing the effects of specific cards as a result. Reanimate is a fairly simple key word, it brings back a copy of a card at the same cost!
Historically, Abyss has been home to highly aggressive decks that often drop their own health total in a high-risk, high-return playstyle. But if that isn't your type of thing, the "Shadow" side of the deck has also been known to offer some exciting mid-range playstyles. The current deck in Worlds Beyond offers players to deckbuild both sides of the equation, depending on the individual's preferences.
The sample decklist here is an example of an aggressive, mid-range deck that aims to flood the board with Bats, Skeletons, and Ghosts (the latter of which can attack the enemy leader on the turn they are played, but disappear at the end of the turn). Cards like Beryl, Nightmare Incarnate are a perfect encapsulation of the aggro playstyle, a card which is overstated for a 2-cost, but requires the user to pay a hefty health cost of 3 when it is played onto the field. Abyss has some of the largest amount of access to direct burn damage in the game, and this deck is not shy about that fact at all. Cards like Aragavy and Rage of Serpents have the ability to ignore the opponent's protection and go straight to the enemy leader. Rounding out the deck are cards that take advantage of the Bats/Skeletons/Ghosts that you bring out over the course of the game. By sacrificing those cards, you can play Reaper's Deathslash or Soul Predation, cards with powerful removal and draw effects to help you clear your opponent's board and continue drawing aggressive options to finish off the enemy leader.
Of course, a much more mid-range or even control version can be played by utilising cards like Medusa, Venomfang Royalty to clear the board and Ceres/Olivia to heal your leader and outvalue the opponent. Which version of Abyss will you pursue? The choice is yours.