If you're talking about making a card that best fits what Batman does, then UB are the only colors necessary I think. Trickery, stealth, and fear are his weapons. There really isn't anything he does that can fit what W cards do in MTG.
If you're talking about in what colors does Batman fit in the color pie (IE, his motivations), then no, B does not fit him well. Fear is a weapon, not a motivation.
Bruce Wayne, The Dark Knight WUB
Legendary Creature -- Human Ninja
Vigilance, intimidate
When ~ enters the battlefield or at the beginning of your upkeep,
look at target player's hand. Then, choose a color. ~ has
protection from that color until the beginning of your next
upkeep.
If you're talking about in what colors does Batman fit in the color pie (IE, his motivations), then no, B does not fit him well. Fear is a weapon, not a motivation.
Modern
Commander
Cube
<a href="http://www.mtgsalvation.com/forums/the-game/the-cube-forum/cube-lists/588020-unpowered-themed-enchantment-an-enchanted-evening">An Enchanted Evening Cube </a>
Legendary Creature -- Human Ninja
Vigilance, intimidate
When ~ enters the battlefield or at the beginning of your upkeep,
look at target player's hand. Then, choose a color. ~ has
protection from that color until the beginning of your next
upkeep.
3/3
Playtesting | Karador, Ghost Chieftain | Narset, Enlightened Master | Ephara, God of the Polis
Established | Gahiji, Honored One | Shirei, Shizo's Caretaker | Opal-Eye, Konda's Yojimbo | Rubinia Soulsinger
Retired | Medomai the Ageless | Diaochan, Artful Beauty