Judas is either the brother or son of James, depending on whether you are reading the KJV or the RSV. Assuming this James to be James Alphaeus, we either have three Alphaeus brothers, or two brothers...
Judas iscariot was the one who betrayed Jesus to the Pharisees for 30 pieces of silver. He took them to the place where Jesus and his disciples where, and then he gave Jesus a kiss, to show them...