I'm sleepy and it's late but might as well get some of this out.

95% chance to:

• Roll a random number 1-12.
  • If this is exactly 9, and you either have some magic skills or some unknown thing to do with ranged weapons, gain ability 9. [precision]
  • If exactly 10 and unknown criteria, gain ability 10 [endurance]
  • If exactly 5 and unknown criteria, gain ability 5 [valor]
  • If exactly 11 and unknown criteria, gain ability 11 [obesity]
  • Any other result not above: unconditionally gain that ability ID.
  • If any check is failed, reroll a new number 1-12 and try again

Otherwise:

• Roll a random number 100-109.
• If this is exactly 102, gain ability 102 [legendary command of undead] if you are not MA Marignon and any one of the following are true:
  • Death magic level > 0
  • Blood magic level > 0
  • Your nation has a value for attribute 210 that is greater than 0 [Lanka, Therodos, MA Ermor, Sceleria, Nazca, Lemuria, LA Ctis]
• If this is exactly 103, gain ability 103 if you have any nonholy paths [adept research]
• If this is exactly 104, gain ability 104 if you have a certain quantity of eyes [third eye]
• If this is exactly 105, gain ability 105 if you have any magic skill and are not mindless [daftness]
• If this is exactly 108, gain ability 108 if you have any magic skill and are not mindless [fast casting]
• Any other result not above: unconditionally gain that ability
• If any check is failed, roll 100-109 again.

If you got ability 7, update your current hitpoints to match your maximum. You gain abilities with a base value of 100.

Hall of fame ability values start at 100. They progress at different rates per turn (all dice nonexploding)