Starforged Handaxe

Weapon (generic variant), rare
  With an enormous array of mirrors (and a touch of magic), starlight can be focussed to such an intensity that the iron within a trapped comet can be gradually wrought into any shape. Such metal is known as starforged iron and is imbued with a unique property that activates as a creature moves towards or away from its target.
  Dopplerstrike. When you make an attack with a starforged weapon you can choose to simultaneously use your movement to move 5 f eet directly towards or away from your target as part of the attack, generating a blue-shift strike or red-shift strike, respectively.
  • Blue Shift. To perform a blue-shift strike your target must be within your weapon’s reach at the end of this 5-foot movement, but does not need to be within your weapon’s reach when you start this movement. You gain a +1 bonus to your attack roll, which deals an additional 1d6 radiant damage on a hit.
  • Red Shift. To perform a red-shift strike your target must be within your weapon’s reach at the start of this 5-foot movement, but does not need to be within your weapon’s reach at the movement’s conclusion. On a hit, the target takes an additional 1d6 cold damage and can’t take reactions until the start of its next turn. A creature that loses its reaction in this way does so before your movement triggers an attack of opportunity.
  Very rare variant: Increase the additional damage to 1d10, and Red Shift’s attack roll bonus to + 2.
  Legendary variant: Increase the additional damage to 2d6, and Red Shift’s attack roll bonus to + 3.