The most common formats are Standard and Expanded
Reach prevents your pesky blue opponents from flying above it and racing
In the hands of the dastardly Maximillion Pegasus in the anime, their signature spell card, "Toon World," has a whole array of ridiculous effects
Orzhov tokens in particular is usually focused on death-by-one-thousand-cuts (if it isnt looping Gary), but Fell Beast quickens the clock considerably, doming an opponent for a chunk on entry and sticking around to keep going
We get a couple new decks to choose from and they introduce a couple new legendaries, but dont have a huge impact on the format
You can Summon it with a new Spell Card that lets you Fusion Summon by discarding cards, triggering the effects of any Dark World monsters used as well as other powerful DARK monsters like the Danger! monsters