First of all, I must say this game has a free +18 patch[jastusa.com] from the publisher. Know that before you play Sorcerer's Choice if you want to enjoy the full experience.

Also, I strongly recommend you play the game without a guide first. The experience is much more interesting that way, and I quite enjoyed how easily is to get a bad ending with Lobelia's the first time I had access to his route. Just do one thing that he doesn't like and... Well, let's not rush into things, shall we?

To trigger the angel's route, you'll have to choose Light at the very start.

Save #1
• Leave the meal on the table.
  
• Resist.
  Save #2
  
• I want to become a grand sorcerer.
  
• Hug him close.
  
• How should I know?
  
• I suddenly remember.
  
• I believe you.

Load Save #1
• Feed him.
  Save #3
  
• There must be a catch.

Load Save #2
• ... I don't know.
  
• Pretend not to notice.
  
• How should I know?
  Save #4
  
• I suddenly remember...
  
• Was that really true?

Load Save #3

• I want to know.

Load Save #4

• Leave silently.

To trigger the demon's route, you'll have to choose Darkness at the very start.

Save #5
• Refuse.
  Save #6
  
• Resolutely refuse.
  Save #7
  
• Return to the library
  
• ...
  Save #8
  
• Let him speak.

Load Save #5

• Reach out hand.

Load Save #6

• Stare silently at the angel.

Load Save #7

• Search for Lobelia.

Load Save #8

• Enough already.