McCulloch Vs. Maryland - Who was McCulloch?

I am doing research on landmark cases of John Marshall. I believe now that I understand the case 'McCulloch Vs. Maryland'. However, I cannot seem to find who Mr. McCulloch actually was.

My understanding of the case is this (this is very basic, i know there are more details and I didn't mention years, but I won't bore you):

In Maryland, the state government imposed a tax on all out-of-state banks. However, the only out of state bank at that time was the Second Bank of the United States, a federal bank. Therefore, there was a state tax on a federal bank.

My question at this point is who exactly sued who - I assume that Mr. McCulloch was a representative of the US Bank, and sued the state of Maryland? Am I wrong in that assumption?

Anyway, Maryland argued in the case that it was unconstitutional for Congress to make a US bank because it was not a power given to them by the Constitution. however, the 'necessary and proper clause', or Article I, Section 8, Clause 18 of the Constitution
Answer:
James William McCulloch was a cashier at the bank. If you read the decision from the US Supreme Court, you would find it there right in the first few paragraphs.

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Probably some random federal government official, maybe from the now defunct national bank.