While Lacerate is a pre-existing skill, which has been reworked in order to join in on the Blood/Sand Stance mechanic, Perforate is a brand new introduction, already a favourite candidate for Melee league-starter builds.
Same as with Bladestorm, Blood Stance seems to favour focusing on a smaller number of targets in close range, while Sand is better used for multiple targets spread across a larger area.
Typically, Lacerate creates slashes once to the left and once to the right. The attack inflicts average damage in two cones going both directions, but the place where the slashes overlap in the middle is a very good damage-dealing sweet spot.
Using Lacerate in Blood Stance has a change to apply bleed as well as inflict bleeding damage. The skill will now start off in Blood Stance by default.
While in Sand Stance, Lacerate will perform much wider slashes, giving players a larger area of damage, as well as a larger area where slashes overlap.
Perforate is simply introduced as a new “low level” skill.
Same as with Lacerate, players start off in Blood Stance by default. While in Blood Stance, striking the ground creates multiple blood spikes which burst through the ground, dealing damage via many hits to closer targets.
Sand Stance’s Perforate creates spikes, which start at the player and spread outwards, hitting enemies in a wide area.