OSRIC to Mothership Conversion

 This is pretty much my OSE to Mothership rules with included tweaks form my previous analysis and the slight adjustments required to go from OSE to OSRIC extra features.

HD +1 = Wounds

HP = Health, if HP is under 10, add +1d5+6 (Allowing 1 or less HD monsters to have between 11-15 Health), add the HD modifier to Health if average not listed.

At the Warden's discretion, really small animals can just keep the HP as Health for being fragile.

If 4 Wounds or higher, deduct 2 Wound and 10 Health for every 3 total Wounds.

If this reduces the new Health total to 10 or less, add 10 to the Health. and round up to the nearest 10.

If the Warden does not like the high Wound and low Health end result, they can halve the Wounds and double the Health.

Combat = 21 -THACO + Any listed modifiers x5 +15, or Ascending Attack Bonus +2 + Any listed modifiers x 5 +15.

Instinct = HD x 10, becoming HD x 5 after 5 HD, as a percentage

Every 4 or fraction thereof of the OSRIC bonus HP becomes an addition +5% to Instinct

(9-AC/AC-10 for Ascending) round down = AP

For NPCs AC becomes (10-AC)/2 with rounding down = AP. This accounts for the original rules OSRIC is derived from miscalculating based on an older edition, prior to printing. If not corrected in future editions to (requiring 9-AC), it remains as such.

d4 = d5

d6 = d10

d8, d10, 2d6 = 2d10

Doubling as you go

Once you get to 4d10, you have the option of changing it to 1 Wound if caused by massive damage.

Bonuses to damage are ignored unless they are +2, then up the dice by one per +2 on the chart prior to converting.

If a + Weapons is required to hit the monster, deduct 1d10 from the damage of the Mothership weapon per + required.

Anytime something that Mothership handles with a percentile roll is rolled on a D6, multiple the chance of that by 16.666 and round up.