You cannot spend points in Darkness until you have Light 24, and the same with Shadow Acrobat and Perception.

If you save up a bunch of ability points, you can spend them to get 24 Light and 1 Darkness, or 24 Perception and 1 Shadow Acrobat. Then you can reload your save to get the points back, and you will still have Darkness or Shadow Acrobat unlocked without having to continue meeting their prerequisites. I'm not sure how useful either of those are, but that's a thing.

It does not seem to work for Weapon Master's different kind of prerequisite. I have not tried yet, but I suspect it would work with Elemental, Berserk, Poison Weapon, Great Sword, Battleaxe, Archery, Long Sword, and Mace's attribute prerequisites as well.