Don DiCorso is a Dwarven don and the ruler of Corso's Chasm. He tends to make high-risk high-reward investments, such as the sale of the magic spoons to the Vistrian government, while his wife Maria handles the regular business.
Personality-wise, the Don is generous to his friends and less so otherwise, which seems to be the norm for Dwarven dons. He was on at least information-selling terms with Don Horatio and also seems to get on well with B'ob, to the point that the latter gave him free information. He rewarded the party generously for each of his quests they completed and kept their lab space for them while they were in Vistria/Urruk/Polaron (although he tactfully reclaimed it the secodn time they left the Chasm).