Achievement: Hear Stab Mastery

[Solau]

How on earth do we complete that? I couldn't see anything in my achievement list for this. I see Mist Slash and Shadow Slash but nothing about Heart Stab.

 

Any help is much appreciated.

 

Solau

[Solau]

Daymn, thanks for clarifying. Been wrecking my head on this

[Shadovvv]

Currently not obtainable. Same with Lotus of Escape.