Rogues and Scrolls

So why do rogues have the ability to cast spells of scrolls(and use magic devices)?

From their first appearance in D&D Sup-I Greyhawk, high-level thieves were given the opportunity to use magic scrolls, with some associated chance of the spell being reversed.

Thieves of the 10th level and above are able to understand magical writings, so any scroll that falls into their hands can be used by them - excluding spells which are clerical in nature. However, with spells of the 7th level and above there is a 10% chance that the effect will he the reverse of that intended (due to the fact that even Master Thieves do not fully comprehend such great magic). [OD&D Sup-I, p. 4]

As usual, some small modifications were made to this rule through AD&D 1E and 2E. In 3E this was transmogrified into a rogue-only skill called "Use Magic Device", which more generally gave that class some random chance to use any magic items which were otherwise reserved for other classes.

The origins of this skill are fairly well known, as similar scenes occur for both Fritz Leiber's the Gray Mouser, and Jack Vance's Cugel the Clever, each whom at some point use magical writings with highly unexpected results. However, I had trouble digging up the specific key passages online, so I figured I'd research, comment, and critique them in a scholarly way here on the blog.

The Gray Mouser's Spell

The following is from the novella The Lords of Quarmall, first published in 1964, later collected in the book Swords Against Wizardry. While Fritz Leiber wrote almost all of the Fafhrd & Gray Mouser stories, the characters were originally conceived by his friend Harry Otto Fischer, with this particular story being the one initiated by Fischer himself. He's reputed to have written the first "10,000 words" circa 1936, with the story being finished and published by Leiber in 1964 -- which by my counting would indicate that Fischer wrote the two setup pieces below, and Leiber the later culmination. (As an aside, the physical descriptions of the two characters were based on Leiber & Fischer themselves -- see more at Wikipedia.) Pages noted below are from the Gollancz Fantasy Masterworks #18: The First Book of Lankhmar (2001).

To follow the action here [SPOILERS follow, of course], it's probably important to understand that the story revolves around two hostile, debauched, magic-using brothers, Gwaay and Hasjarl, each controlling part of an enormous labyrinthine fortress that extends into the bowels of the earth ("... certain passageways beneath it ran deep under the Sea and extended to certain caverns wherein might dwell some remnant of the Elder Ones", p. 681). Gwaay (who has hired the Mouser) has a group of 12 sorcerers of the First Rank serving to defend him from magical threats. Meanwhile, Hasjarl (who has coincidentally hired Fafhrd) has a group of 24 sorcerers of the Second Rank (i.e., lesser) constantly employed in trying to send magical diseases and plagues at Gwaay. And thus we have --

In the opening scene:

"If it's magical helpings you lack," the Mouser retorted boldly, "I have a spell or two that would frizzle your elder brother's witches and warlocks!" And truth to tell the Mouser had parchment-crackling in his pouch one spell -- though one spell only -- which he dearly wanted to test. It had been given him by his own wizardly mentor and master Sheelba of the Eyeless Face. [p. 672]

Later:

His tone was unmistakably rebuffing, nevertheless the Mouser, dreading a dull evening, persisted, "There is also the matter of that serious spell of mine which I told you, Prince -- a spell most effective against magi of the Second Rank and lower, such as a certain noxious brother employs. Now were a good time --" [p. 691]

Much later, as events rise to a climax -- in Gwaay's Hall of Sorcery, at the table with the dozen major magicians:

"... And by the blood of that one whom it is death to look upon..."

So sonorously invoked the Mouser, as with eyes closed and arms outstretched he cast the rune given him by Sheelba of the Eyeless Face which would destroy all sorcerers of less than First Rank of an undetermined distance around the casting point -- surely for a few miles, one might hope, so smiting Hasjarl's warlocks to dust.

Whether his Great Spell worked or not -- and in his inmost heart he strongly mistrusted that it would -- the Mouser was very pleased with the performance he was giving. He doubted Sheelba himself could have done better. What magnificent deep chest tones! -- even Fafhrd had never heard him declaim so.

He wished he could open his eyes for just a moment to note the effect his performance was having on Gwaay's magicians -- they'd be staring open-mouthed for all their supercilious boasting, he was sure -- but on this point Sheelba's instructions had been adamant: eyes tightly shut while the last sentences of the rune were being recited and the great forbidden words spoken; even the tiniest blink would nullify the Great Spell. Evidently magicians were supposed to be without vanity or curiosity -- what a bore!

Of a sudden in the dark of his head, he felt contact with another and a larger darkness, a malefic and puissant darkness, of which light itself is only the absence. He shivered. His hair stirred. Cold sweat prickled his face. He almost stuttered midway through the word "slewerisophnak". But concentrating his will, he finished without flaw.

When the last echoing notes of his voice had ceased to rebound between the domed ceiling and floor, the Mouser slit open one eye and glanced surreptitiously around him.

One glance and the other eye flew open to fullness. He was too surprised to speak.

And whom he would have spoken to, had he not been too surprised, was also a question.

The long table at the foot of which he stood was empty of occupants. Where but moments before had sat eleven of the very greatest magicians of Quarmall -- sorcerers of the First Rank, each had sworn on his black Grammarie -- was only space....

Very quietly he stood up and silently walked in his ratskin moccasins to the nearest archway, across which he had drawn thick curtains for the Great Spell. He was wondering just what the range of the spell had been, where it had stopped, if it had stopped at all. Suppose, for instance, that Sheelba had underestimated its power and it disintegrated not only sorcerers, but... [p. 728-730]

As it turns out, the Great Spell has in fact disintegrated all of Gwaay's sorcerers to a fine gray ash, and not touched any of Hasjarl's sorcerers (or anyone else). A few pages later:

His voice trailed off. It had occurred to him to wonder why he himself hadn't been blasted by his own spell. He had never suspected, until now, that he might be a sorcerer of the First Rank -- having despite a youthful training in country-sorceries only dabbled in magic since. Perhaps some metaphysical trick or logical fallacy was involved... If a sorcerer casts a rune that midway of the casting blasts all sorcerers, provided the casting be finished, then does he blast himself, or...? Or perhaps indeed, the Mouser began to think boastfully, he was unknown to himself a magus of the First Rank, or even higher, or -- [p. 732]

And a little bit later, as the Mouser and his companion speculate on their next move:

Ivivis frowned. "Gwaay used to say that just as sword-war is but another means of carrying out diplomacy, so sorcery is but another means of carrying out sword-war. Spell-war. So you could try your Great Spell again," she concluded without vast conviction.

"Not I!" the Mouser repudiated. "It never touched Hasjarl's twenty-four or it would have stopped their disease-spells against Gwaay. Either they are of the First Rank or else I'm doing the spell backwards -- in which case the tunnels would probably collapse on me if I tried it again." [p. 740]