Perhaps it's an additive thing and Kastral used up many of the copies in circulation, allowing Keeper to spike now
All fusion monsters have effects that punish or restrict Special Summoning in some way, as well as all having the effect that they add a "Shaddoll" spell or trap card from your graveyard to your hand when sent to the graveyard (these ones can be triggered by anything)[/spoiler] [spoiler=Shaddoll Monsters] While not necessarily the best or most powerful, Beast has a very useful send effect indeed, allowing you to draw a card, which is literally always useful
If nothing else, this card punishes cantrips, so if youre into Ian Malcolm, better draw a bunch of cards in one effect
Number 103: Ragnazero X WATER Rank 4 [ Fairy / XyzEffect ] ATK 2400 DEF 1200 2 Level 4 monsters Once per turn (Quick Effect): You can detach 1 material from this card, then target 1 Attack Position monster your opponent controls, whose current ATK is different from its original ATK
Trap Hole Finally, we get to the classic Trap Hole