A strong event record transforms your existing collection into resources for expanding that collection further
They also feature a neat resource manipulation tool that triggers whenever they successfully complete a challenge, stripping resources away from the opponent's hand
Dimir Guildmage deserves a special note for being able to eliminate your opponent's hand in the late game, while Cavern Harpy provides an easy combo to repeat your creatures' come-into-play effects
It's also notable that the effect only applies when creatures on the battlefield are exiled - it's no use exiling creature cards from hands or graveyards, which means my first instinct of pairing this guy with various iterations of the MTG planeswalker Ashiok won't work
The mill ultimate is neat but doesnt really synergize with the rest of the card, though cards like Sphinxs Tutelage and Psychic Corrosion can turn the draw from its front side (and lets be honest, youre playing blue so you will draw cards) into some library damage
Unless you have a very clever combo for its simple effects
