"For matters majestic,
the King elects
To neglect the domestic."
Benjamin acts as an advisor to Don King; possibly like a consigliere.
Benjamin is apparently not a Transylvito Vampire.
Ben appears again in LIAB Text 34 reciting (or perhaps only thinking) a piece of Rhyme-o-Mancy in which he criticizes Don King for spending schmuckers on Jillian and Faq. Since he is 'cancelling the antsy' with his rant, it may be that Benjamin is the only thing preventing Caesar Borgata and the warlords from carrying out a coup, or perhaps he's merely calming himself.
Perhaps that Benjamin is similar to Wanda in being proficient in many magical disciplines outside his own, but unlike Wanda, and more like Sizemore in actually finding them fascinating. In real life, Ben Franklin was a brilliant polymath: a scientist famed for his work with electricity; publisher and author of Poor Richard's Almanack, including assorted epigrams, minor poetry, and weather forecasts in it; a mathematician who explored "magic squares"; and one of the major political leaders of the American Revolution against King George III.
Real World References
Benjamin's name might come from the slang use of "Benjamin" to reference large sums of money, due to the appearance of Benjamin Franklin on the U.S. hundred-dollar bill. (On-Line Slang Dictonary)