Zenkaro served under Sheeva during an Earthrealm invasion at a volcanic crater. The Shokan had an extreme advantage over the Earthrealm defenders, especially after a bone-headed move by Sonya Blade that got Kurtis Stryker injured and Sonya herself suspended from action.
As Sonya and Stryker were escaping, Zenkaro placed a tracking beacon on their Dragon Jet to locate their base of operations. When it was located, Zenkaro and his elite forces slipped away from the battle to invade the base, believing that the base would be taken easily with only Stryker, Sonya, and Kiba to guard it. However, Sonya and Stryker were able to reduce their numbers and Sonya defeated Zenkaro.
Zenkaro seemed to be somewhat of a sexist, as he belittled Sonya a bit during their short fight.
In order to keep the location of their base a secret, Raiden banished Zenkaro and his elite men to the Realm of No Return.