Lvl 34 Sewers I
Kuko will let UltraLow kinda fly through Act 2, especially in Maggot's Lair and the Arcane Sactuary.

I spent one skill point in Redemption when getting close to Radament. Some of the skeletons around are cold immune and can't be shattered, so I wanted another option for corpse disposal. Radament spawned Extra fast PI - I nailed him against the wall letting him feel a mix of elemental dmg from Kuko and Holy Shock beside the speeded up merc attacks (50% fast cast).

  Lvl 35 Dry Hills
Most critters in Act 2 have low or no resists and are easy targets for UltraLow. He cold even fight a Holy Freeze Swarm boss pack in Far Oasis without a single backstep.

  Lvl 36 Maggot's Lair III
Coldworm the Digger was found pretty quick - Maggot's Lair II could be completly skipped as the exit connected directly to the entrance. This time I shopped Lysander for some Antidote potions before getting close to the poison spitter - a good idea if you have -70 poison resists. I placed UltraLow at a position outside the room where he could fire arrows towards the worm. Geschef's task was to freeze all Sand Maggots childs before they could do any harm to UltraLow. That way the battle was over in under a minute, which is at turbo speed compared to the longish fight in Nightmare. Another proof to Ian's theory that Hell is easy ;).

  Lvl 37 Claw Viper Temple I
Vipers are easy meat for UltraLow :). Mummies/Skeletons are a bit harder and killed Geschef several times. A cold wizard is no real help here anyway, so UltraLow had to do without him for a while. Claw Viper Temple II requires some caution, as their is no space to retreat except going back to level one. I always try to clear the upper area first, opposite to where Fangskin (LE CE Extra fast Manaburn CI) spawns normally. After done that, I lured Fangskin to the upper area and shot arrows at him at a certain angle which avoided all the sparks. Funny thing - I picked up a blue ammy (I do this only now and then), and it turned out to be a perfect amulett of the Whale. I would call that a perfect timing (of the Whale requires lvl 37). After the Mesh belt found in Act 1, this is already the second of the Whale item. Seems the game wants to say me something ...

And I listened. Equiped belt and ammy and said goodby to Angelic Wings/Halo which had helped so much earlier on. Combined with a rare ring (20% fire resists 13% lightning resists 2 MDR) and some further Charm tweaking UltraLow had 1063 life and 66/29/73/-65 resists - and an AR of 292. I don't care about 23% chance to hit when using an autohiting bow ;).

  Lvl 38 Arcaine Sanctuary
Skipped the Palace more or less - visited Fire Eye tough (FE/LE Extra fast Fanatic FI). It took a while until I could find a position for UltraLow from where he could kill the runner without too much danger.

Ah Arcaine Sanctuary. Some builds may have trouble with the PI ghosts, not so UltraLow. Goatman are killed easily too, only Vampires require a bit more treatment. The Summoner was found in the third branch visited (I could avoid the Escher like one which I prefer to take last). Shot a bunch of arrows in his direction and the quest button turned red already.

  Lvl 39 Tal Rasha's Tomb
This was a PITA in Nightmare - it required more than an hour to find the way to Duriel. So how long will it take it now ? Only 9 minutes ! Ok I had more luck finding the right way, but still ... Of course UltraLow killed everything on the way, and one critter dropped a Felloak. You need a weapon with 60% lightning resists ? I have one for you.

With nearly 1100 life I felt ready for Duriel. I dumped everything from the inventory not needed for this battle and filled the space up with healing potions. Switched to Smite gear and into the Chamber. Started smiting at Duriel but gave up after a while because only a sliver could be removed from his life bar that way. No shield and Kuko has to do it. Of course I did not start a run and shoot tactic but let UltraLow stay in melee range trying to avoid the charge attacks. I had to open the inventory and start drinking potions from their, as only some full rejuvs were left in the belt. Doing this I realized I had made a mistake - I dumped all TP scrolls from the belt (the TP book was removed during the charms tweaking earlier on) and forgot to put a scroll in the inventory instead. Oh well - I ran out of healing potions and had to quit the game. Ok, I rejoined, filled up with healing potions and rejuvs and into the chamber again to remove the remaining 1/3 of Duriel's life bar, but this victory has a bad taste. Sidenote: Duriel ignored the cold merc, so he survived the whole battle, but was totally useless of course.