Yuisis was another of the characters touched by a rebalance last year and another one that got huge improvements out of it. She's gone from being awkward to use to being one of the strongest ticketable auto attackers in the element.
Her kit is:
1) Two modes, Heavensbane mode and Starslayer mode. One focused on attack, one focused on defense. The first has 30% unique atk mod and lowered hostility. the second has 50% boost to def and higher hostility. You switch between modes with her first skill.
2) Second skill has either substitute + 70% cut (Starslayer mode) or a huge 150% unique mod + 80% ca dmg cap up (Heavensbane mode) for one turn. Both on 5 turns cooldown.
3) Third skill has either Counter on Damage for 2 hits (Starslayer) or 3 turns of guaranteed DA (Heavensbane)
4) She gains Chivarly levels at every ougi (and at every mode switch if you pick her EMP). Chivarly levels raise her CA Dmg and CA Dmg Cap (Heavensbane) or Charge Bar speed+Healing (Starslayer).
5) Her ougi gives 20% echo in Heavensbane mode and Drain in Starslayer mode.
Believe me, It's harder to explain than it is to use as you can see from the video. Unless you need to tank huge attacks you can safely stay in Heavensbane mode for most of the fight and just keep hitting.
A shame I didn't manage to get her summer skin last year. *cries*
