Warhammer: Mark of Chaos - Chaos Campaign - Chapter 4, Mission 1

Here are general tips for playing the Chaos Champaign in Warhammer: Mark of Chaos, on HARD Difficulty. At the end of Chapter 1, Mission 6, we chose Nurgle instead of Khorne. A list of all our Warhammer: Mark of Chaos articles can be found here.
We won't be hand-holding you through absolutely everything, but instead just give tips on situations that we found tricky or that you might not have considered.

Chapter 4: The Rise of Chaos

Mission 1: Hammer of Justice

Overview

• No time limit, so take your time. Use the Twisted Crown of the Horned Rat to heal your heroes if you are trying to use them solo or using them to take point and provide a distraction for your missile troops to shoot without getting stuck in melee. Remember that you can move items around by dropping them and then having another hero pick them up.
• There is a non-regenerating Warpstone Pinnacle that can give you 50 HP of troops. Decide what free models you want and bring them.
• Walls provide cover IF you do not stand too close to it because the cannonball still has a blast radius.
• Once the cannon spots you (because a dwarf regiment has spotted you), it will not stop firing even though your regiments may be back in the fog of war after you have killed all nearby enemies.
• The cannon stops firing when the Captain is killed.
• At the staging area, just to the west, is a wall. Hide all non-essential regiment there. Take a single useful regiment with you to keep your team small and make it easy to get cover for the entire attack force.
• A good regiment to take is the Clanrats, because their ability to envelope enemies can save you from having to chase down broken-morale regiments. However, any regiment will be fine as your Grey Seer can recover their numbers.
• Once you can gain the foot of the hill or get onto the hill where the cannon is set up, you are safe even if the cannon turns all the way around to point at you.
• Leave the cannon alone until you clear the rest of the map and secure the Warpstone Pinnacle.
• Secure the Pinnacle last because until you do, it is considered neutral and won't be a target for the enemy.