Sun and Moon Slash

Sword Attack. Attack target foe twice. These attacks cannot be blocked.

Sword Attack. You attack target foe twice. Unblockable.

[edit] Acquisition

Hundred Blades or Conjure Frost/Flame/Lightning synergize well with Sun and Moon Slash because you attack target foe twice, effectively dealing double conjure damage, as does any other effect that benefits from hitting your target (e.g. Life Draining from Vampiric weapon mods and Order of the Vampire, etc.)
Unlike Dual attacks, both attacks from this skill hit simultaneously, meaning both hits will connect even through skills such as Shield Bash or Shield of Judgment.