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Congratulations Fleece on becoming an Oracle!
My screenshotting program is having trouble nowadays, graphical glitches in the top-left corner :(
Yep, Oracle is the continuation of Priest (no options like 2nd to 3rd class). I'm a Marksman, which is the continuation of Archer, and Gavriil and Saryah are both Cardinals, the continuation from Bishop.
More: These are called "Master Class" (MC) classes, and come with a new skill tree which you cannot completely max out. You run around doing quests to gain 'Talent Points' (TP) which unlock parts of your Skill Tree, and you can earn up to 5 TPs. It would take 9 TP to fully unlock your skills.