Arjac Rockfist, Grimnar's Champion

If a unit contains at least one model with this special rule, and that unit arrives on a random table edge (due to Outflank, or other special rules), then you can re-roll to see which table edge they arrive from.

A unit that contains at least one model with this special rule automatically passes Fear and Regroup tests. When it Regroups, the unit does not make the 3" Regroup move, but can instead move, shoot (or Run) and declare charges normally in that turn. Furthermore, if a unit containing one or more models with this special rule is caught by a Sweeping Advance, they are not destroyed, but remain locked in combat instead.

If a unit contains at least one model with this special rule, and that unit is charged, every model with the Counter-attack special rule in the unit gets +1 Attack until the end of the phase.

If, when charged, the unit was already locked in combat, the Counter-attack special rule has no effect.

When a unit that contains at least one model with this special rule takes Morale checks or Pinning tests, they ignore any negative Leadership modifiers. If a unit is both Fearless and Stubborn, it uses the rules for Fearless instead.

Arjac Rockfist must issue and/or accept a challenge whenever possible. In addition, he re-rolls all failed To Hit rolls when taking part in a challenge.

Independent characters can join other units.  They cannot, however, join units that contain vehicles or Monstrous Creatures.  They can join other Independent Characters, though, to form a powerful multi-character unit!  Independent Characters pass Look Out, Sir rolls on a 2+. A unit that contains one or more Independent Characters does not need a double 1 to Regroup if reduced to below 25% of its starting numbres, but instead tests as if it had at least 25% remaining.

Full details in BRB. Rule too long to copy verbatim.

Arjac Rockfist can only join a unit of Wolf Guard or Wolf Guard Terminators. If Arjac Rockfist is included in a Detachment that includes at least one unit of either Wolf Guard or Wolf Guard Terminators, he does not take up a slot on the Force Organisation Chart.