yes, increasing the acolytes lust then returning Roushk to the temple after telling Othra to tell everyone about the purified lake and not mentioning the corrupted lake will give you the corruption ending for the tribe's storyline.
Like Toothless said, choose all the red options when you talk with Othra before you confront Roushk. Just make sure that the total lust points of the warriors and acolytes are 10 or more combined .. But only if you want the bad ending for them.