8 cards where the mana value < 5 and the power >= 8 and the color identity ≤ BU

Death's Shadow (Double Masters #82)
Desecration Elemental (Duel Decks: Mirrodin Pure vs. New Phyrexia #57)
Eater of Days (Darksteel #120)
Ludevic's Test Subject // Ludevic's Abomination (Innistrad #64)
Ludevic's Test Subject // Ludevic's Abomination (Innistrad #64)
Phyrexian Dreadnought (Mirage #315)
Phyrexian Soulgorger (Coldsnap #141)
The Ancient One (The Lost Caverns of Ixalan #222)
Westvale Abbey // Ormendahl, Profane Prince (Shadows over Innistrad #281)
Westvale Abbey // Ormendahl, Profane Prince (Shadows over Innistrad #281)

The arc of my blade has carved a path of light to the end of these results.