User blog comment:Hyperion602/A new way to play Vayne/@comment-8506165-20140217192540

You don't need Black Cleaver. The breakeven point for Vayne's DPS to benefit significantly from ArPen over, say, another Phantom Dancer is unreasonably high or non-existent, due to Silver Bolts. This was from an analysis concerning Last Whisper, but it'll be more true if anything for Black Cleaver.