Here's a list of where you start the quest.
Plains Walker/Wind Rider - Black Cat in Hunters Village
Destroyer/Titan - Tazki in Rune
Sword Singer/Sword Muse - Raien in Aden
Spel Howler/Storm Screamer - Fairen in Ivory Tower
Phantom Summoner/Spectral Master - Fairen in Ivory Tower
Blade Dancer/Spectral Dancer - Mordred in Hardins Academy
Necromancer/Soultaker - Hardin in Hardins Academy
Shillien Knight/Shillien Templar - Galadrid in Hardin Academy
Shillien Elder/Shillien saint - Anastia in Hardins Academy
Hawkeye/Sagitarius - Bernard in Hunters Village
Paladin/Phoenix Knight - Sedrick in Aden
Spellsinger/Mystic Muse - Arkenias in Ivory Tower
Silver Ranger/Moonlight Sentinel - Bernard in Hunters Village
Warsmith/Maestro - Telson east outside of Rune
Prophet/Hierophant - Hollint in Oren
Dark Avenger/Hell Knight - Mordred in Hardins Academy
Tyrant/Grand Khavatari - Hakran in Rune
Phantom Ranger/Ghost Sentinel - Bernard in Hunters Village
Abyss Walker/Ghost Hunter - Black Cat in Hunters Village
Bounty Hunter/Fortune Seaker - Mond east outside of Rune
Temple Knight/Eva's Templar - Sinden in Aden
Elven Elder/Eva's Elder - Hollint in Oren
Elemental Summoner/Elemental Master - Arkenias in Ivory Tower
Gladiator/Duelist - Sedrick in Aden
Warlord/Dreadnoughts - Aiken in Aden
Warcryer/Doomcryer - Rahorakti in Rune
Overloard/Dominator - Rahorakti in Rune
Bishop/Cardinal - Hollint in Oren
Sorcerer/Archmage - Valleria in Ivory Tower
Warlock/Arcana Lord - Kinsley in Ivory Tower
Treasure Hunter/Adventurer - Black Cat in Hunters Village
