This skill is a Special Rule that is only available to specific Star Players. Please visit this page to find a list of current and past Blood Bowl Star Players.
SlayerOnce per game, when an opposition player with a Strength characteristic of 5 or more is Knocked Down as the result of a Block action performed by Grim, you may apply an additional +1 modifier to either the Armour or Injury roll. This modifier may be applied after the roll has been made.
This special rule could be useless if the opposing team doesn’t have any players that are strength five or higher. In games that do have them you have two choices, either use it straight away as soon as it makes the difference between breaking armour or not. Or look to save it for an injury roll where the extra +1 will change the result up to the next injury bracket. A lot of the stronger players tend to have quite high armour. There are some that have slightly lower armour, so you might want to play it by ear depending on the particular opponent and also perhaps what turn in the game you are on.