For those who don't know Hydro, he was featured in the MK comics.
Hydro: Sub-Zero's best friend and fellow Lin Kuei, Hydro has the ability to control water and even blasted strong waves of water that were so freezing cold that they could actually freeze the opponent upon contact. He is a bit younger than Sub-Zero, but is a respectable fighter in his own right. He also carries two ninja swords on his back.

Could this really be him?