Marlin Academy is an Alabama military school. Edwin Spangler was commandant of the academy for the first two seasons and beginning of season 3. He ruled the school with an iron fist (read: claw) and hates cadets who disrupt authority with insurrection.
Lois Wilkerson had sent her eldest son, Francis, there after piercing his nose and getting arrested for destroying a neighbour's car. His insurrection and rebellious nature caused Spangler to clash with him a lot. Francis emancipates himself and leaves school in season 3's Houseboat, with the help of an unscrupulous, cheap lawyer.
This ends up incurring Lois' wrath because she was against him leaving school from the start. Spangler goes to visit Francis and he reminds his former commandant that he was emancipated hours ago. If he wants to look at the legal papers again, Francis is more than happy to show them. Spangler tells him that he doesn't need to and thanks Francis for freeing him of his boredom at the school with his rebellious nature. After he leaves, Spangler is fired when a cadet reported him drunk and abusive to the other cadets to the local authorities. Charges were filed against him after more cadets claim his abuse to them, After losing his job, the humiliated Spangler follows Francis to Alaska in his attempt for revenge against his former cadet. It is unknown what becomes of the school or other cadets since Emancipation was the last time the school was seen on screen. In Dewey's Dog, it's revealed that Spangler was fired from Marlin Academy for an incident that lead to the cadet complaining to the police and charges were filed against him. According to him and although he couldn't remember the incident, Spangler remembered who was the cause of all of his problems: Francis. Therefore he made the trip to Alaska to claim Francis.