Nine mana is a hefty price to pay for Hand of Emrakul
Then when Neriv swings you'll exile a number of cards from your library equal to the number of differently named tokens you control
Getting anything bigger than a 1/1 token is already pretty rare, and usually requires access to green in the color identity to pull off
For one, Delighted Halfling is a better Cavern of Souls on a creature because for one green mana, Delighted Halfling is a 1/2 Halfling Creature with the ability to add one mana of any colour to cast a legendary spell that cannot be countered
Only this time, we're not looking at Yu-Gi-Oh, but instead at Magic: The Gathering
Not only does it give other alliterative creatures you control flying too, but whenever you cast any alliterative spell you get to scry 2 - looking at the top two cards of your deck before putting them on the top or bottom of your library