Upon getting a 'grand slam' with rank 5, a small animation appears and a short round of applause can be heard.Rank 4 is compulsory once the player has it, they will not ignore friendly or neutral targets, and the circumstances under which Rank 5 will decapitate rather than cripple are not well-understood. You now do double damage with a melee weapon, and gain a chance to cripple your opponent, or grand slam their head clean off! You now do 80% more melee weapon damage and hit all targets in front of you. You now do 60% more melee weapon damage and gain an increased chance to disarm your opponent. You now do 40% more melee weapon damage and gain a chance to disarm your opponent. Swing for the fences! Do 20% more melee weapon damage.