I wouldn't expend too much effort keeping him captive. After restarting several times to keep him imprisoned and warding off the Mountain Garus without allowing them to attack the barricades, the AI just dropped 3 AoE spells on the barricade to free him. Not much you can do about that... It cheats my precious! It cheats!
Played this campaign a couple of ways but the easiest seems to be spamming grobles and ghosts in an IS/FW. Despite the "wrath runes only" verbiage, you can run Protectorate runes so long as you have a Wrath shrine. The rock eaters are nice but the BG plays almost as well with no exotics/legendaries/limited which means you can pretty much finish this scenario off with runes that are easily available. Constructs with physical immunity clog the lanes which slows down the juggernaut. Ghosts whittle down the enemy by create lots of blue on blue kills. IS equips like Tactical Manual and Granite Bracers make the two boss units (lieutenant and mystery elf) far more effective and survivable. After that, you can fill in with whatever floats your boat. I ran with some Whistperghast and Shadestrikers and Rip Witches and Coven Claws; either were nice for laying down champs and using both in the same BG was effective. Remember some healing (I went divine favor route) and you are guaranteed to win, even when you get an uber bad drop on leg 2 with all those garus. Your odds of having something that will slow them is just too great.
Well damn.... Yeah man sometimes my champs are spawned way in the back or like right next to the garus. like wtf....
