"Defiler Magic In Original D&D" Topic

Once upon a time back in the 90s, I ran a Dark Sun campaign using the AD&D 2nd edition rules. (If you are unfamiliar with Defilers and defiling, you can check it out here: link ) I thought the Defiler magic was a VERY interesting twist on spellcasting. So much so that I am considering dropping into my OD&D-S&W-DD-Etc campaign. My roadblock is that the original Defiling rules are more complicated on their own than the entirety of mishmashed rules I am currently using.

My first thought was that defiling could be most easily treated as "casting a spell using defiling allows the spell to be cast before any other actions in the round, but causes all vegetation within a number of yards radius equal to the spell level to turn to grey ash." This would also stimulate some roleplaying opportunities.

I am curious what the collective OD&D Hivemind can suggest regarding this. I am interested in ideas about casting defiling spells by normal Magic Users, not in pursuing a separate Defiler class.

Thank you for any and all discussion.

Sounds like a simple solution. I'm not familiar with Dark Sun, but maybe have the desolation increase geometrically by spell level:
1st level: 10-yard radius
2nd level: 50-yard radius
3rd level: 100-yard radius
4th level: 500-yard radius
5th level: 1,000-yard radius
6th level: 1-mile radius
7th level: 2-mile radius
8th level: 5-mile radius
9th level: 10-mile radius

You could also have defiler magic dry up water sources.

I wasn't familiar with Dark Sun or defiler magic in the different editions, but I skimmed through the article you linked (thanks for that).

Start with what is the downside to using defiler magic? What are the game penalties? Make them consequential, like losing SAN in Call of Cthulhu, or again from CoC, like permanently giving up Magic Points to cast some important spells, which you can regain at that cost of SAN. NPC spellcasters in CoC were insane, so these penalties don't affect them, but they matter to players, since a failed SAN roll means losing control of the character.

Defiler magic is its own incentive (higher Initiative, more powerful spells). So tie its use to those penalties.

Thanks, guys. I have some ideas gathered from other forums as well, so I am going to synthesize something sweet and simple tonight or tomorrow. Then I will share it here :-)

Alrighty, here is what I came up with; it is largely a re-write of the defiling-for-Preservers rules in Dragon 202.

Defiler Spell Casting

Additional Spells
By using defiling magic, a magic user may cast a spell that he has already cast, or he can cast one he still has memorized without losing it from memory. A magic user has access to a number of bonus defiler spell levels (not spells) equal to his current experience level minus one. The bonus spell levels can be used only to cast spells that the magic user has memorized, or to cast spells that he had memorized and expended. The bonus spell levels only apply to one battery of memorized spells; they cannot be accessed again until the magic user has had a chance to replenish his normal spell selection.

Decreased Casting Time
Casting a spell using defiling allows the spell to be cast before any other actions in a round.

Defiling Conequences
A defiling spell causes all vegetation within a number of yards radius equal to the spell level to turn to grey ash, and cause notable discomfort or even non-damaging pain to all living things within this area. There are also social consequences; Lawful beings will be repulsed by the caster's disregard for the life around them, and should be roleplayed accordingly.