Everywhere you go, people are afraid of you.  They respect you greatly, and you will most likely never see a person to disobey you.  With this trait, you can get away with things that others can't, like minor criminal offenses and disrespecting nobles.  This said, you can mainly get away with refusing to pay for food at taverns you visit, or charging citizens money to use certain public shortcuts.  You can also critique others openly without harsh disregards.  Also, you always have a place to dock your ship, and you have free passage as long as your letter of recommendation from your former Captain remains in your possession.

The name gives it away, you stay with your city more than you go out on the High Seas, and you are a tyrant to your people.  You rule with an iron fist, and you appoint governors of similar interests to do your dirty work.  You force people out of their rights, and whether they go along with your rules or not, everyone knows what you expect.  Oppressors have many different tactics to get their subjects to become slaves for them.  Some force their people into a huge army, and some hold gladiator games year-round.  Whatever your fancy, you use that tactic to make your people relent, and you are known to enforce the laws so strictly so rebels won't have any leeway.  The life of Oppressors calls to you- you are a violent charlatan with a dose of power much too bigger than you deserve and need.

While you are within your city, you conduct an Aura of Law around you.  For twenty squares extending in all directions, anybody who can see, hear, or smell you in that range has to succeed on a DC 12 Wisdom save or be unable to commit any acts against your laws for the next hour.  You can use this ability as many times as you want, but every time after the first 3, the DC drops by one level.  For example, if you had already conducted an Aura of Law 3 times, than the new DC for people to beat is 11, since 11 is one less than 12 (the start for the first 3).  The DC and number of tries resets after a long rest.