I think for both Deathwatch and Grey Knights, we need more rules support for being a Space Marine - whether or not the PCs can be members, the GM might want fully fleshed out rules for permanently attaching NPC allies to the party, so they're not working with just a quick and dirty NPC statline. Here's my attempt: Geneseed Organs: While these are not cybernetics, any increase from a geneseed organ counts as a cybernetic increase, and hence will not stack with themselves or cybernetics, and cannot raise a characteristic above 5, unless otherwise noted. They are listed separately so the GM can more readily modify a Space Marine who may be missing some (such as an Imperial Fist). Geneseed mutations of some known chapters are included to give a starting point. Secondary Heart: +2 wounds. Ossmodula + Biscopea: +1 Brawn, +1 Resilience. Black Dragons have an overactive Ossmodula. They are Mutants with the Bone Blades Malignancy, but the bone spurs are permanently extended, so they do not suffer wounds each time they attack with them. Haemastamen: +1 Athletics. Larraman's Organ: Space Marines do not bleed out. The Critical Injury table is now 126-140: Gruesome Injury. Catalepsean Node: Needs half as much sleep as normal, and can go up to 2 weeks without sleep before needing to roll against sleep deprivation. When recovering strain via Cool or Discipline (i.e. via rest), Advantage symbols also heal 1 strain, not just Successes. Preomnor: Decrease the difficulty of any Resilience check made to resist the effects of ingested toxins twice. Net advantage symbols on Survival or Streetwise checks to forage for food and water may be converted to successes on a 2 to 1 basis, but any food and water found this way is neither edible nor potable by normal human standards - count them as Easy ingestion toxins that inflict Critical injuries if the consumer fails the check (the Marine should normally succeed without rolling, as he reduces the difficulty to a step below Simple). Omophagea: Consume flesh and blood to recover memories from the corpse as determined by the GM; the flesh must still have viable DNA. Memories are usually completely random, but the Space Marine can attempt a Discipline check to recover specific memories or additional detail, which has a base difficulty of Hard, upgraded once, as the Mind Scan effect of the Compel psychic discipline. Blood Angels and many of their successors have an overactive Omophagea. They must succeed at a Hard Discipline check not to both consume their enemies and attempt the Discipline check to recover specific memories. If they fail (either to resist the urge or to experience specific memories), the GM may spend 1 Despair to give them the Zealous Fury mental trauma, or increase said trauma by one step. Blood Angels start with the Frenzy talent, even if their talent pyramid would not normally permit it. Multi-Lung: Reduce the difficulty of any Resilience checks to resist airborne toxins once, and survive without air for thirty times as long as normal: a Space Marine can breathe water, and can typically hold his breath for an entire encounter. Treat him as environmentally adapted to thin atmosphere. If he passes his suffocation threshold, he suffers 1 strain per round while suffocating, rather than 3. Occulobe: Ignore penalties for poor lighting, not including absolute darkness, and +1 to Perception and Vigilance when Vision is the prevailing sense. Lyman's Ear: Ignore penalties for noise, and +1 to Perception and Vigilance when Hearing is the prevailing sense. +1 Coordination. Sus-an Membrane: On a 141-150 on the Critical Injury table, or with a Hard Discipline check, the Space Marine enters permanent stasis: he will not die due to the End is Nigh critical injury, does not age, and does not need to eat, drink, or breathe. He is considered permanently incapacitated and sleeping, and is totally unaware of his surroundings. The Space Marine will exit this state only when the appropriate drugs or hypno-therapy are administered; Space Marine Apothecaries are normally simply taught this, but otherwise it is a Hard Forbidden Lore check to figure out what the appropriate treatment is. Imperial Fists do not have a Sus-an Membrane. However, they start with the Durable talent at rank 1. Melanchromic Organ: Decrease the difficulty of any Resilience check made to resist ionizing radiation (such as gamma or ultraviolet) twice. Raven Guard have a malfunctioning Melanchromic Organ, giving them white skin and black eyes. Only decrease the difficulty once for them. They inexplicably distort reality around them; Raven Guard start with the Knack For it talent at rank 1, assigned to Stealth. Salamanders have an overactive Melanchromic Organ; decrease the difficulty three times for them instead. Salamanders have pitch black skin and red eyes. They also have slow reaction times; when rolling for Initiative using Vigilance, add 1 Setback. Oolitic Kidney: This works like a Chem Gland cybernetic implant that only produces de-tox, but no Discipline check is needed to activate the organ. Neuroglottis: +1 to Perception and Vigilance when Smelling or Tasting is the prevailing sense. +1 Survival. Mucranoid: Space Marine Apothecaries know how to make the drug that triggers this; otherwise, it is a Hard Forbidden Lore check to know it. When triggered, the Space Marine essentially sweats out an environment suit: he is environmentally adapted to heat and cold, and suffers only 1 wound per round while exposed to hard vacuum, rather than 3. However, he suffers 1 setback die to all Agility checks. Betcher's Gland: This is a ranged (light) weapon, allowing the Space Marine to spit a slightly corrosive contact venom. Space Marines with this Gland are immune to this venom's blinding effect. Damage 3, Crit 6, Range Engaged, Burn 6, Slow-Firing 1. If the Marine makes a called shot to the target's eyes and hits them (i.e. not any eye protection the target is wearing), the target must make a Hard Resilience check; if it fails, it is Blind for 1 round per Failure plus 1 round per net 3 Threat. Imperial Fists do not have a Betcher's Gland. Progenoids: These have no mechanical benefits to the Marine - he simply serves as an incubator for both of them. Black Carapace: Treat this as an arbitrarily large number of Interface Ports combined with a Mind Impulse Unit. Hypnotherapy: +1 Cool, +1 Discipline. Space Wolves: Space Wolves inflict the Test of Morkai on their Aspirants, which forces them to become Exorcised Mutants as a result of both daemonic exposure and consuming the Canis Helix. They do not roll for their Exorcism Malignancy, nor can they choose their Mutant malignancy; the two malignancies are Bestial Hide and Razor Fangs. Space Wolves also have Claws, allowing them to make unarmed attacks using the Knife profile, provided they are not wearing gauntlets to get in the way. Their Fangs may be used to deliver their Betcher's Gland venom - treat them as Toxic 3, but instead of resolving the wound/strain damage Toxic normally inflicts, resolve the blindness effect of the venom. Blood Angels: Blood Angels have a mutation in their Omophagea, causing them to be Mutants, and the long-lasting psychic imprint of Sanguinius' Death renders them Exorcised as well. Like Space Wolves, they cannot choose their Malignancies; they have Bloodlust and Cannibalistic Urge. When a Blood Angel suffers mental trauma, it is automatically Zealous Fury. They start with the Frenzy talent. Black Templars' geneseed is slightly Untouchable - not enough for the Elite Advance, but anyone with psyker abilities who receives their geneseed dies a horrible death, and anyone who has their geneseed will never develop psyker abilities. This includes psychic talents and Wyrd. I didn't get into Grey Knights since the current ruleset doesn't cover Sanctic/Malefic, so it's challenging writing a rule forcing them all to be psykers.