Michael "Dirty Mike" Rickenburg is a character roleplayed by Vader. He is a homeless person and often refers to himself as a ''hobo''-lord. You will see him mostly robbing and killing people, also with a sign in his hand begging for money.
If you want to stay on his good side, you better give him money - or sleep with one eye open. Dirty Mike has a so called 'deathlist' in which he writes the name of people declining to give him money, calls him names or expresses their disgust of his smell. If you are on his deathlist, he will let you know in many ways.