Who is Mavers from A Test of Wills and what is their importance?

The local rabble rouser, Mavers had a long-standing feud with Charles Harris, even while Harris was paying him a pension initially to help take care of Mavers's mother, then later to prevent him from getting into real danger. Mavers is cruel enough and intelligent enough to stir up a lot of trouble in the village, but his alibi for the morning of the murder is airtight.