Cyberpunk to Call of Cthulhu

Back in the 90s, someone converted Call of Cthulhu 5.5E and Cyberpunk 2020 to each other in Interface Magazine.

The trouble was the magazine only covered about half of the conversion to CoC.

I found the magazine and finished off the conversion a few years ago except for Magic which I never quite got round to doing. Maybe someday someone else will try.

I also did a bunch of stuff for Call of Cthulhu 7E, which is the latest edition.

Interface V2 #2

Summarized here for space reasons, round up in character’s favour

CoC Attribute	Cyberpunk 2020 Conversion
SIZ	(BOD x 1.2) + 6
STR	(SIZ -3) w/o Strength Feat OR (SIZ) + ½ Strength Feat Skill
CON	(SIZ-3) w/o Endurance Skill OR (SIZ) + ½ Endurance Skill
DEX	(REF - 1) x 2
APP	(ATTR – 1) x 2
INT	(INT + TECH) x 0.6 + 6
POW	(COOL + LUCK + EMP) x 0.6
EDU	INT + Education/General Knowledge Skill

 

Call of Cthulhu % Skills: (Attribute + Skill Rating – 4) x 6

If Converted skill is less than Cthulhu Base Skill, use Base% + 5%

There is a mistake with the skill conversion rules in Interface, where they deducted 6 rather than 4. Someone with 10 REF and 10 Pistol should have a 96% chance to hit rather than 84%.

Cyberware is bad for the Soul/Sanity, every 15 points of Humanity Loss deducts 1 from a POW Maximum of 21 in CoC 6e and prior. In 7e, that means Max POW and Max SAN drop at a rate of 1 per 3 HL.

Biomonitors give +20% to resist torture or drugs

Booster/Speedware give double the Cyberpunk value initiative, so +1 is +2 (6e) or +20% (7e)

Smartgun is +20%

Number of Skill Chips is half INT/Base INT, +1 = 20%, +2 = 30%, +3 = 40%, high is +5% per +1

Implants/Cyberoptics and Cyberaudio have same effect. Audiovox gives +10% to Sing, +2 Perception from a device is +15% to Listen/Spot Hidden (7e)/Search (5e and prior)/See (5e and prior)

Cyberlimbs are assumed to have an innate STR of 20/100, with Thickened Myomar limbs having STR of 25/125 and Hydraulic limbs having a STR of 30/150. All can do D3+DB crushing damage and don’t forget to account for that limbs massive new DB. Hydraulic Ram hands do D6 damage, Buzzhand dos D10+1 and a Spik does D4+2. HP and AP are calculated like before of halving the SDP and SP of the limb.

Linear Frames raise the STR of characters.

Epsilon	20/100
Beta	25/125
Omega	30/150

 

For Bioware, Grafted Muscles add +4/+20 STR,+2/+10 SIZ. Bone Lace adds +4/+20 STR, +1/+5 SIZ

Skinweave is 6 AP, Enhanced Antibodies or Nanosurgeons raise haling to D6 per week, combined it is D10 pr week. Toxin Binders give +4/+20 to CON rolls against toxins and poisons only.

Body Plating gives AP 12 or whatever the listed special effect is.

Cyberweapon	Damage	DB (Yes/No)
Scratchers, Big Knucks	D3+2	Yes
Vampires	D3	No
Rippers, Slice N’ Dice	D6	Yes
Wolvers	D8+1	Yes
Cybersnake	D4	Yes

 

The interface article detailing the Cyberpunk 2020 to Call of Cthulhu/BRP conversion advised to treat The Net as another reality like the Dreamlands, where you physically go even if your unconscious body remains. In that case, treat the Programs like Spells, with the difference between the Program Strengths being added to either the Resistance Table for BRP/CoC prior to 6e, or the x5 percentage difference added to the opposed roll for CoC 7e. IE. 4 vs 3 is a +1 to the Resistance Table before rolling or multiplied by 5 and added to the opposed roll for +5% regardless of the method. The effect of the Programs should be respected even if there are too many to summarize.

Digitizing Mythos Texts.

Computers cannot cast spells (unless you want them too)

Putting a mythos text under an OCR scanner and loading a book onto a datachip is legal, halve the Study Time, and makes the Hard Roll a Regular Roll to learn a spell (6e & 7e)/ Increases Spell multiplier for Tome by 1, eg. x3 to x4 (5e and before). However, SAN Damage is Maximum rollable.

Cyberpunk Roles

Edgerunners (the in-universe term for the characters) frequently gain and lose cash on new gear and can fit nearly every asset they value into a duffle bag. Therefore, adjustments of the Credit Rating are required. First, for this “Future Era”, take the Modern Era table in the 7e Call of Cthulhu book and halve the values for Cash, Assets and Spending Limits, or take the Classic Era and Double the values for Cash, Assets and Spending Limits as the Keeper sees fit to emulate the desired tone. For converting over Cyberpunk 2020 characters, halve the new value for Assets again. This represents the fact that the Eurobuck is the preferred currency in 2020 and are worth twice as much as USD. But add the value of the Specialty Bonus to the Credit Rating to determine the Cash rating only. This is the bonus you get by multiplying your Specialty Skill by two as laid out in the Interface article. Characters created in Call of Cthulhu don’t use Specialty Bonuses because their skill points total should cover that.

Interface also suggests using the Specialty Skill x2% as a general-purpose skill bonus for Cyberpunks in the right situations. Cops get Authority +2-20% added to their Persuade Skill while flashing their badge etc.

Suggested 7e conversion of the Professions based on the Cyberpunk 2020 core book. For characters created in Call of Cthulhu, just use the professions already there.

Rockerboy ED x2 + APP x2 – Bonus: Charismatic Leadership

Spot Hidden, Art and Craft (Specializations), Disguise, Fighting: Brawl, Choice of (Fast Talk or Persuade), Charm and Two Additional Skills Suggested CR 9-65

Solo EDU x2 + (STR x2 or DEX x2) – Bonus: Combat Sense

Spot Hidden, Firearms (Handgun, Rifle and Submachinegun), Fighting (Brawl), Climb, Stealth and One Additional Skill Suggested CR 20-60

Cop ED x2+ (STR x2 or DEXx2) – Bonus: Authority

Spot Hidden, Firearms (Handgun), Fighting (Brawl), Climb, Intimidate, Psychology, Law and One Additional Skill Suggested CR 9-55

Corporate ED x4 – Bonus: Resources

Spot Hidden, Library Use, Psychology, Charm, Disguise, Choice of (Persuade or Fast-Talk) Accounting and One Additional Skill Suggested CR 15-65

Media ED x2 + APP x2 – Bonus: Credibility

Spot Hidden, Art and Craft (Photography), Psychology, Listen, Choice of (Persuade or Fast Talk), Charm, Library Use, One Additional Skill Suggested CR 9-60

Fixer EDU x2 + (DEX x2 or APP x2)

Spot Hidden, Arts & Crafts (Forgery), Firearms (Handgun), Fighting (Brawl), Locksmith, Sleight of Hand, Intimidate, Choice of (Persuade or Fast Talk) Suggested CR 15-60

Techie EDU x4 – Bonus: Jury-Rig

Spot Hidden, Electrical Repair, Mechanical Repair, Electronics, Locksmith, Science (Engineering), (Science (Cybernetics), One Additional Skill Suggested CR 9-70

Netrunner EDU x4 – Bonus: Interface

Spot Hidden, Computer Use, Electrical Repair, Electronics, Arts & Craft (Brain Dance) Science (Mathematics or Cryptography) Science (Cybernetics), One Additional Free Skill Suggested CR 9-60

Med Tech EDU x4 – Bonus: Medtech

Spot Hidden, Choice of (Electrical Repair or Mechanical Repair), Library Search, Psychology, Science (Biology), Science (Pharmacy), Medicine One Additional Free Skill Suggested CR 18-70

Nomad EDU x2 + (STR x2 OR DEX x2) – Bonus: Family

Spot Hidden, Survival (Desert), Choice of (Electrical Repair or Mechanical Repair), Firearms (Rifle), Fighting (Brawl), Drive Auto, Climb, One Additional Skill Suggested CR 9-30

Science (Cybernetics) is 01% skill like all science and represents the specialized Cyberpunk 2020 skill of Cybertech: “The required skill for repairing and maintaining cyberwear.”

The Interface article said to ignore MA when converting characters, but the way CoC handles MOV, means there is a good chance the an Edgerunner with BOD-enhancing Bioware and not a lot of skill points put into Strength Feat if converting from Cyberpunk 2020 will end up with a SIZ high enough to make them MOV 7. While that is fitting, it also is unintentional, so I decided MOV bonus = (MA-8)/2, which means only the very fastest get anything. Any Cyberware that increases MA is also divided by 2.

General and Cyberpunk 2020 to Call of Cthulhu Guns and Gear

Cyberpunk 2020 Armor should be halved to get Call of Cthulhu values. Yes, it’s powerful, halve it again if you want but even unmodified Call of Cthulhu gave generic Kevlar body armor 7 AP. My personal house rule is that the AP degrades by 1 after being hit on a Hard Success (1/2 Skill for 6e and prior). To reflect the underused Cyberpunk ruling that SP degrades if penetrated.
Perhaps adapting the flat values to rollable armor like Cthulhu Dark Ages/Stormbringer. This also introduces a measurable change from Soft Armor, represented in the corebook by Light Armorjacket with SP14 to Hard Armor represented Medium Armorjacket with SP 18. Also, the never seen SP30, which is merely theoretical.

Fixed SP/AP	Rollable AP	Fixed SP/AP	Rollable AP
4/2	1d3-1	16/8	2d4
6/3	1d4-1	18/9	1d8+1
8/4	1d6-2	20/10	1d6+1d4
10/5	1d6-1	24-25/12	2d6
12/6	1d8-2	28/14	1d8+1d6
14-15/7	1d8-1	30/15	1d8+1d6+1

Look up the Cyberpunk 2020 weapon and check its damage on the table below. Additional damage bonus is halved, but if the damage is +3 or higher, upgrade the damage to the next category up.
I.E. 2d6+1 damage in 2020 converts to 1d6 damage in Call of Cthulhu and 2d6+2 becomes 1d6+1. But a gun doing 2d6+3 or 2d6+4 becomes 1d10. A 3d6+2 weapon would do 1d10+1 and so on.


12 Gage Shotguns remain 4d6/2d6/1d6 for legacy reasons
Flamethrowers remain 2d6 for legacy reasons
 
For Call of Cthulhu, The formula is half the 2020 value and +2 if the dice is 5, 9, 13 or 17 and +3 if it is 3, 7, 11, 15 or 19, I don’t know if there are any damage values that go above 20d10. Or for 6e and prior editions, change the d10s to d6s and add +2 to odd numbers of dice except 1d6.
Look at the Rate of Fire (RoF) for Cyberpunk 2020 guns, it is a lot more granule than Call of Cthulhu. For a pistol, the maximum number of times it can be fired per round is 3 regardless of anything else. Equivalent in Shadowrun to [SS mode] if RoF 1 and [SA mode] if RoF 2, this gun can also be fired as Burst 2, but nothing in Cthulhu has Burst 2 to compare it to. Guns which have RoF 3 to 9 have Burst 3 as an option, or if that is indicated by the gun description as an option, equivalent to Shadowrun [BFA mode], otherwise they have Full-Auto. A RoF of 10+ is Full Auto, Shadowrun [FA mode].
Malfunction rating is VR – 97% S – 95% UR – 92%
WA is converted by converting WA that is -2 or under and +2 or higher, to a penalty/bonus dice respectively.
Ranges appear to be Considered Close (1/4) of 2020 ranges in meters, then converted into yards. Rounding up to nearest 5.
Putting it together: Militech Ronin Light Assault Rifle – Firearms (Rifle). Can’t be Hidden. Common. Damage 2d6+1. Base Range 110 yards. Uses per Round: 1 Burst 3, Full-Auto. Mag 35. Cost/Future -/-/EB450. Malfunction 97%. Common in Era Future.
Hand to Hand damage, look up the 2020 damage rating for the hand to hand attack, then convert it and convert the Call of Cthulhu damage to d3 with the following equivalencies: 1d6/2 = 1 1d6 = 1d3 1d8 = 2d3, 1d10+ = 3d3. So a super cybered-up strike that does 10d6 becomes 2d10+2d6 which becomes 2 x 3d3 + 2 x 1d3 = 8d3 + DB.