Hydro was a warrior from Earthrealm and a member of the Lin Kuei clan. He appears in the Blood & Thunder comic books and Mortal Kombat: Legacy.
In the comics, Hydro was a close friend of Sub-Zero (Bi-Han) and traveled with him to fight the forces of Outworld. He had the ability to control freezing water. Hydro was killed by Scorpion in Outworld as part of the undead wraith’s vow of killing all of Bi-Han’s friends and family (before killing Bi-Han himself).
In Legacy, Hydro is portrayed as an earlier version of the cybernetic ninja program (unit LK-1V1) and is pitted against Cyrax and Sektor to demonstrate their superior abilities. Hydro showed to have the upper hand against both Cyrax and Sektor at the beginning, but was ultimately bested by both cyborgs and killed by Cyrax.