|Tailtiu gets Wrath+Darting Blow 3 on her weapon.
Wrath+Luna almost guarantees deaths with a double attack.
Sturdy Impact prevents her from dying from DC units. Also, adaptive Damage can't kill her very well because of balanced Res.
Darting Blow + Flashing Blade make sure that her activation rates remain high on Luna. However, glimmer might be a better option if you want a unit that can beat Guard reliably.
Finally, Null Follow-up removes wary fighter, tomebreaker, and other skills from the picture, and instead makes the interaction rely on speed (which she gets in spades).