One of our kill team (Ultramarine Librarian) had his innards burnt away by a critical hit, he lived through it and he had his toughness reduced by half. My question is how would this be remedied/treated using the rules for bionics and replacement organs and how much of his toughness should he regain/recover. Would he be invalided out of active service as his toughness as now so low?

If his toughness is simply reduced to half, then his toughness characteristic will heal as per the rules for healing permanant characteristic damage.

You can use the machine trait for illustrazting the repair done to the SM torso.

His inwards will be remade adn the SM will be combat reeady.

herichimo said:

Thanks, I wasn't even aware of this rule, I'll look into it.

Brother Anselm said:

thats just made a marine very happy, now all he has to do is get through the rest of the scenario on zero fate points and hope he earns another as a reward