Worshipper – “Conquest” [Campaign 2, Mission 3]

Have you tried studying more useful skills in the first mission to apply them in the second? Also, you can quickly (as much as possible) capture the mines (which are nearby) and head east from the lower Elven city, kill the Rakshasa, enter the Keymaster's tent, and open the outpost near the Inferno castle. Then you can proceed as suggested by HRodo.XDDDDDD