Water Xiao Lin (Xiao Lin)

Xiao Lin (Water Kung Fu Girl) is a must have attack monster for the brand new content, after Raid Dungeon update she became one of the best resources for almost all attribute dungeons. She have a high base defense that makes her suitable for raid and rift of worlds and despite she has a low base attack considered her type (attack), her skill multipliers makes a huge contribute on DPS.
The main problem with her could be on HP, that are pretty low and incompatible with a R5 run, so there's why most of endgame player use Vampire runes on her.

To better understand the mechanics around this monster you have to take a closer look to her skills and the sinergy between them:

Her first skill attacks a single target and with a certain chance will fire her 2nd skill, Shadowless Kick, attacking an enemy to decrease its Attack Bar by half and its Attack Spd for 2 turns.
This Water Kung-Fu Girl combo enables her as a great unit for necro (1/3 multihitter on the first skill + spd debuff) and as dps due to great multipliers, also her third skill strikes 4 times on random targets (single target if boss) and the damage scales by 15% for each debuff on the enemy, so imagine this on a raid boss usually stacked with harmful effects.
Additionally if this skill is on cooldown, she have a 1/4 chance to counterattack when someone attacks you.

These are the main reasons why Xiao lin the Water kung fu Girl is an OP unit particularly in Raid 5.

Despite someone will tend to think her as an alternative to Hwa (Fire Rakshasa), this other unit deals significantly less damage than water kung-fu girl who possess an entire skillset useful for raid, she deals lot more damage and can be placed even in front line if Vampire with proper def% substats.
Generally speaking you would consider to bring both units in your team, so they'll reduce the boss turns, because hwa will lower the runes requirements for healers and cleanser while the kung-fu girl will work as a pure damage dealer with attack bar reducer as a bonus and def break the boss on auto attack.

Necropolis Dungeon B10

Here she works nice as a speedy DD multihitter, speed reducer and def breaker, with her first skill she gets another hit every 3 and it works in sinergy with the third skills which enable her to counterattack with 25% chance. Couple Xiao Lin with lushen to speed up your run.

For this purposes she can be runed Violent and Revenge to get the most out of the counterattacks and to maximize the numbers of hits per second.
Builded properly she can deal 70k and plus damage with skill 3 and 2-3 debuffs on the boss but also great on killing your team when stolen, so not so suitable in common fire team for nb10, in this case you would consider
to use a more killable nuke-runed Fuco (Wind Lich).

Xiao Lin in Dragon B10

Used in team with Julie, Verdehile, Galleon and Spectra to clean the dungeon in less than 90 seconds

It is also notable that her Water Dragon Attack could be a real nuke in the Rift of World Dungeon due to the big amount of harmful effect usually given to the boss.

Xiao Lin rune build

PvP oriented: Rage/Blade - SPD / %Crit damage / %ATK or %ATK / %Crit damage / %ATK

Violent build: Violent/Focus or Violent/Nemesis - SPD / %Crit damage / %ATK or %ATK / %Crit damage / %ATK

Raid 5 Build on backline: Vampire/Blade or Vampire/Revenge - Atk%/Cd%/Atk% with speed and cr substats