Reading through the grapple rules for RT/DW while one enemy is controlling the grapple- it seems both players must fully commit to the grapple. As a GM- this seems useful since having large amounts of enemies could hold multiple space marines to inactivity especially with benefits from assistance. However- during a grapple the only way of dealing damage seems to be through the "Damage Opponent" option under Controller Grapple Options.

In a situation where a lictor has grappled a space marine with it's feeder tendrils from a distance. With it's large strength, enormous size, multiple arms, it has no difficulty in controlling the grapple. But can it really only do 1d5-3+SB primitive damage? Even at max, 14, it has no ability to pierce the astartes power armour. Are there any rules that allow other attacks to be made during a grapple? Can, after winning the opposed strength test deal damage with his natural weapons rather than counting as unarmed? Can the same be done with a space marine with a melee weapon (even though a space marines unarmed damage doesn't count as primitive)?

If there are no rules for it, would it be too much to handle if creatures or players with natural weapons be able to attack with them during a grapple, rather than dealing unarmed damage? In natural weapons a creature is considered armed even when not wielding weapons. Thus in grapple- when he does unarmed damage he instead deals his natural weapon damage. This isn't exact based on the rules- but it seems to make sense.

Reading the Grapple rules on page 240, under Damage Opponent, it does say "he inflicts his unarmed Damage". Now I know what the following bit says but that may just be there to remind the player what standard unarmed damage is. After all, if you have Unarmed Master talents your unarmed damage is increased so I'd say you'd use this instead.

So as far as the Lictor goes I'd let it use a single unarmed Lictor claw attack.

Another thing to point out is that if you control a grapple you may make a Ready action and (next round) a Use Item action. Now, as far as I can see it doesn't mention not being able to use weapons. The way I envision it is (for example) a Marine manages to wrestle his opponent and whilst holding him in a Grapple he readies his Melee weapon (knife, chainsword or what have you). Then on the next round if the foe didn't manage to get away, the marine plunged it into his foes gut / cuts his throat / bashes him on the head with the hilt, etc.

That's how it reads to me anyways.