Here is what I came up with, to play Conan with my old D&D Mentzer boxed sets. I guess it would work with C&C, too.
Classic D&D Hyborian Age setting guidelines
Background
At character creation the cultural background must be chosen.
Barbaric: reduce by 1 the chance of being surprised. The lowest ability score must be mental.
Civilised: add 1 to all reaction checks. The lowest ability score must be physical.
Classes
The Fighter
As standard D&D fighter, with the following special ability:
Combat specialization: at 2nd level fighter characters can choose a weapon with which they gain a +1 bonus to attack rolls. They must choose whether this weapon is used mounted (cavalry) or on foot (infantry).
The Thief
As standard D&D thief, with the following special ability:
Eyes of the cat: at 2nd level thieves “have eyes like a cat”. They gain infravision 60’.
The Noble
Primary requisite: Charisma
Hit dice: d6
Armour: all
Weapons: as Thief
Saving throws: as Cleric
Attacks: as Cleric
XP table: as Cleric
Special abilities:
Wealth: the character starts with 200 sp (besides the normal allotment), and he receives this sum every year, provided he does not squander the money publicly.
Rally: retainers have a +1 to their morale score.
Leadership: at 4th level nobles double the number of retainers they can have for their charisma.
Diplomacy: nobles add +1 to any reaction checks.
Do you know who I am?: at 9th level (name level) characters who may fear the noble's reprisal must make a saving throw vs. spells to take action against the noble.
The Scholar
Primary requisite: Intelligence
Hit dice: d4
Armour: none
Weapons: dagger, blowgun, net, whip, staff, mace, sling, club, short bow, spear, javelin
Saving throws: as Magic-User
Attacks: as Magic-User
XP table: as Magic-User
Special abilities:
Knowledge is power: this ability refers to knowledge of ancient history, arcana, artifacts, fables, lost lore, mysteries, occult and relics. It assures full literacy and numeracy. This skill gives one a range of knowledge in fields of study that others are not likely to know. It allows the character to know (or at least know where to go to learn) about a particular subject or issue related to the above mentioned subjects. It also increases the character’s chances of locating items of interest in lost tombs, books in libraries, or other related activities.
The percentage chance of success follows the progression of the Thief's Hear Noise ability. If the result of the check is larger than double the chance of success, the information gained is completely wrong and misleading.
Decipher script: as 4th level Thief.
Spells: scholars can cast spells. The Magic-User table gives the number of spells which can be cast each day for each level, although no spell memorisation is necessary. Scholars do not need spell books, although these can be used as sources to learn new spells. Scholars start with one sorcery style (and basic spell) at 1st level. At 2nd level they gain another sorcery style and another basic spell. At 4th level and every four levels thereafter, they gain another sorcery style and related basic spell. From 3rd level onward, they gain one advanced spell per level.
Ancient language: scholars know one ancient language of their choice.
I assigned levels to the spells in the d20 Conan book and Scrolls of Skelos, and I am converting them. Here is the list of spells and spell levels:
CONAN RPG: SPELLS BY STYLE AND LEVEL
Counterspells
Warding (B) 1
Greater Warding 4
Incantation of Amalric's Witchman 1
Rune of Jhebbal Sag 2
Master Warding 6
Curses
Lesser Ill-fortune (B) 1
Awful Rite of the Were-beast 6
Curse of Yzil 4
Dance of the Changing Serpent 4
Draw forth the Soul 6
Gelid Bones 2
Greater Ill-fortune 3
Ill-fortune 1
Doom of the Doll 6
Invocation of Xuthalla 6
Shrinking Doom 5
Divination
Astrological Prediction (B) 1
Dream of Wisdom 4
Mind Reading 3
Psychometry 1
Sorcerous News 5
Greater Sorcerous News 6
Visions 3
Visions of Torment & Enlight. 5
Projection 6
Hypnotism
Entrance (B) 1
Dance of the Cobras 3
Dominatio n 3
Dread Serpent 4
Hypnotic Suggestion 2
Mass-hypnotic Suggestion 5
Ranged Hypnotism 5
Savage Beast 3
Boundary 6
Dance of Atali 6
Enslave 4
Illusion 5
Swell 4
Torment 1
Voice of Power 6
Voice of Power, Greater 7
Nature Magic
Summon Beast (B) 1
Animal Ally 2
Children of the Night 3
Greater Summon Beast 1
Sorcerous Garden 5
Nature Magic (continued)
Bones of Life 6
Control Magical Beast 4
Control Monstrous Humanoid 5
Fruit of Air 7
Necromancy
Raise Corpse (B) 2
Agonising Doom 6
Black Plague* 6
Greater Black Plague* 7
Death Touch 5
Draw Forth the Heart 6
Oriental Magic
Calm of the Adept (B) 1
Darting Serpent 2
Shape-shifter 6
Warrior Trance 2
Yimsha’s Carpet 6
Prestidigitation
Conjuring (B) 1
Burst Barrier 2
Telekinesis 2
Telekinesis, Greater 2
Animate Statue 3
Animate Swords 2
Magic Builder 5
Summonings
Master Words and Signs (B) 6
Demonic Pact (B) 1
Demonic Pact, Greater* 6
Summon Demon* 4
Summon Elemental* 6
Banish Outsider 6
Bind Demon 7
Form Demon 6
Immortality
Witch’s Vigour* 4
Eternal Youth* 5
Life Drain 6
Unnatural Strength* 6
Vampire Transformation* 6
Cosmic
The Time is Right* 6
The Stars are Right* 7
B = Basic spell
* = potential runaway magic