Let’s take a closer look at the instruments of destruction that Imperial Knights use when they tired of shooting the big guns.
Imperial Knights have some of the most deadly guns in a game of 40k. But, sometimes they want to cut loose with a little close combat. Let’s learn a little more about these instruments of death.
Via Lexicanum:
Reaper Chainsword
The Reaper Chainsword is a smaller type of Titan chainsword carried by Imperial Knights. Once at the beginning of human colonization of space this chainswords used for tree-falling. 
Though only the height of three men, the Reaper’s adamantine teeth are no less deadly. When swung with all the power of the Knight’s servo-motors, the Reaper is capable of cleaving through practically anything, from the thick ferrocrete walls of a defensive bunker to a Super-Heavy Vehicle. The very sound of this chainsword has been known to cause enemies to flee.
Thunderstrike Gauntlet
The Thunderstrike Gauntlet is a smaller type of Titan power fist carried by Imperial Knights. Crackling with destructive energies, the Thunderstrike Gauntlet allows the Knight to rip apart its enemy, even tearing limbs off of Titans.
When used as a bludgeoning instrument the gauntlet releases a deafening thunderclap upon impact, so powerful it is capable of hurling Battle Tanks through the air to land amongst the enemy and crush them beneath the vehicle’s weight.
