Class-As-Species (Anatomically Correct Wizards)

Adventurers are different from all other kind of folk in every aspect, mainly as a result of their class. But nobody seems to know what a class is other than it makes you better at killing shit and getting fat stacks. What if we took it in an absolute direction:

Fighters, Thieves, Wizards and the like are not occupations, they are all species that appear human on the surface, but are anatomically unique. 

All branching evolutions come from and still inherit the traits of:

ADVENTURER 𝚫 - AURUM FICEDULA
If you take any other class-as-species Delta, you must take this Delta. Be born (or rebirthed) with numinous qualities.

• With a mere look you know any given object's monetary value.
• You give off pheromones that have a certain effect on people. People treat you as more important than you often actually are.
• You metabolize gold. All other food tastes like ash, but gold? Indescribable ambrosia. You must adventure to live - your appetite is voracious.

A flock of Adventurer subspecies (called a Party)
(By Konstantin Vavilov)

FIGHTER 𝚫 - URSUS LORICATUS
If not born a Fighter , you can be reborn as one by: Bathing in the burning blood of a dragon and melting into a Fighter; Wearing a piece of armor for a month without ever taking it off; Divine blessing.

• What people mistake for a suit of armor is actually your flesh. Add [LEVEL + 1] to your AC. You are never treated as unarmored, as it is embedded into your skin.
• Your sympathetic nervous system works wonders. When in extreme danger, pick either fight or flight. If you choose fight, gain +1 attack per round and you cannot die until you are out of danger (but can still be damaged and dismembered while in danger). If you choose flight, gain +[LEVEL] Dexterity, run twice as fast, and clamber up surfaces like a mountain goat.

THIEF 𝚫 - ACUTI CATTUS
If not born a Thief , you can be reborn as one by: Embracing a grue with mutual love; Drinking Cocoon Poison from the Underworld and waiting a month; An unholy pact.

• The tips of your fingers are sharpened like fangs (count as dual-wielding knives if unarmed). You are immune to poisons that are transmitted by skin contact.
• You make no sound you didn't intend to make. Your eyes look like those of a cat.

WIZARD 𝚫 - MAGICIS PARISITIS
If not born a Wizard, you can be reborn as one by: Eating a lich's phylactery; Placing your soul in a hat and renouncing your humanity; ; Drinking the wrong potion.

• You are not a humanoid, instead you are a parasitic hat piloting a body. If placed on the head of a creature with [LEVEL] or less HD than you, you can pilot it. Creatures get an Intelligence save to resist. Even if the creature is not magical, you have an inherent 1 MD.
• You can smell magic. Different schools of magic have different scents. Cinnamon for pyromancy, vanilla for necromancy, onion for illusions, etc.