Tad-Smith Althorp Smith
Harrington House Treasurer
From Rockstar's Official Site, in the Facebook section.
Derby Harrington's Great Grandpa was the one whom built the Harrington House.
And Each of the 5 Chapters focuses on one of the cliches.
I'll put up the sources, once I find where I found them.
Theory:
About Tad-Smith's Parent, based on the clips released.
I found that:
1. That His Father is a self-made man (rag to riches)
2. That his Dad married his first cousin.
The second statement is based upon Tad-Smith saying:
1. That first cousin are legal
2. That he respond angrily at a student for being called an inbred.
