Grip
Typically used with: Muscle.
In short: hang on. Awe your onlookers with your fearsome wall-scaling abilities. Clutch onto a bucking bronco. Catch a wet bar of soap. Any great feat of strength using your hands and fingers only (or feet and toes, for that matter) is what the Grip skill is all about. Grip can be used to effectively ascend or descend vertical distances as well as maintain solid holds on objects or creatures.
Climbing
You can roll a Grip check to climb out of a pit, up a tree, down a cliff, over the city walls, or across a ledge. The tougher the surface is to climb, the higher the DL.
The ladder into a tree house should be DL 5, and a sheer cliff face should be DL 30. A smooth, flat surface is basically impossible for mortals to Climb short of using magic spells. If you use climbing equipment, you gain a +4 bonus to the Grip check. A device such as magnetic boots, while not magical, allow for climbing of flat, metal surfaces at a DL of 10.
If you fail the check, you fall from your starting point. Not so bad at the bottom, but deadly from the top. See the Guard skill about falling damage.
Depending on how far you're climbing, your GM may ask you for Stamina checks or risk falling. If you're trying to go especially fast (or at least faster than someone else), you'll also want to roll a Dash check. If you're carrying something or someone, you also want to roll a Might check.
Once you start climbing, you gain the grabbed condition (in this case you're wrestling the wall). It's really hard to climb and fight at the same time. A character cannot perform any action that requires the use of two hands (e.g. swing a greatsword) unless, say, the character has more than one set of arms.
Catching
If you want to snatch something out of the air as it zooms past, you can roll a Grip check. The tougher the object is to grab, like being slippery or heavy, the higher the DL. The object needs to be within arm's reach, otherwise you have to roll a Gymnastics or Dash check to get near it first.
If you're climbing, you can try to catch an object or creature that falls from above you. If you fail, whatever it was continues falling. If you roll a Critical Failure, you follow suit in proper arm-flailing fashion.
Grabbing
You can roll a Grip check to grab onto another creature ("Get over here!"). Any time you try to grab a creature, combat begins and the GM should make everyone roll Reaction. See the "Grabbing" entry in the Tactics section of Chapter 10: Combat. Your opponent can prevent or escape your Grab by surpassing your Grip check with a Might check (if they're strong) or a Thievery check (if they're agile). As long as you have a hold on them, you both gain the grabbed condition.
Contests of strength between creatures of different Size favor the larger creature. In these opposed combat rolls, the larger creature gains a +4 bonus for each point of Size difference. Thus, if a kulgeri attempts to Grab a firnoy, the kulgeri receives a +8 bonus to his Grip check.
Disarming
You and another combatant can vie for the same held object ("It's my locknar"). If you make a successful Called Shot attack to the defender's held object, you make opposed Grip checks. Whoever has the strongest grasp gets to keep it. See the "Disarming" entry in the Tactics section of Chapter 10: Combat.
If a larger creature attempts to disarm a smaller one, the larger one receives a +4 bonus to this check for each point of Size difference.
Resisting Disarms
When someone tries to disarm you in combat, you roll a Grip check and they roll either a Thievery check (if they use a weapon) or a Grip check (if they use hand-to-hand). See the "Disarming" entry in the Tactics section of Chapter 10: Combat. Certain types of weapons, especially those that require two hands to use, grant a +2 bonus to the Grip check. If you meet or exceed the opponent, you keep your weapon.
If a smaller creature attempts to disarm a larger one, the larger one receives a +4 bonus to this check for each point of Size difference.