Its a powerful, flashy ability, which can easily generate interest for creating a deck
Emet-Selch, UnsunderedEmet-Selch, Unsundered The front side of Emet-Selch, UnsunderedEmet-Selch, Unsundered is a nice collection of abilities, and the condition to transform Emet-Selch isn't all that difficult to accomplish given the amount of self-mill available in Dimir
Web-slinging is an alternate casting cost that lets you return a tapped creature you control to your hand to play a spell, similar to Ninjutsu but more flexible since the creature doesnt need to be unblocked
Typically, having very few cards in your library is a nightmare scenario, so cards like Doomsday or Leveler are trying to enact a harsh penalty that turns out to be a boon
Still, Yuriko feels a bit too powerful sometimes, so mono-black is an option if you need a more mid-level ninja build
The return of Icy Manipulator was a boon for Fourth Editions Royal Assassin, as it had its combo back, and the ability to tap and render Meekstones or Winter Orbs effect nullified for your untap phase was widely used