Vengeance for Davian Thule

Map	Siwal Ruins
Briefing	Commander, we have located Captain Thule's attacker. The Warrior beast that you drove into the Badlands has resurfaced, leading a swarm of lesser Tyranids. This is our first chance to strike back at the Tyranid enemy, and we cannot pass it up. Collecting samples from this creature's corpse may also lead us to a cure for Captain Thule, and could give us valuable information on how to defeat the hive fleet. This area is heavily infested, Commander, so be prepared for heavy resistance.
Objectives	Avenge Captain Thule
Elite	Opponent uses superior troops.
Bio-Feedback	Victory reduces infestation (-1)
Bonus Intelligence	This target is vulnerable to bolter fire. Swarms of Gaunts and other hive creatures defend this target.
Reward	Missile Launcher

Walkthrough

This walkthrough assumes Primarch difficulty.

This mission is one of those where upping the difficulty level doesn't seem to make it overly much harder. The only goal is to kill the boss-level Tyranid Warrior up north. Capturing the Automated Foundry at the east corner is recommended, and you should clear the map of all Tyranids; the time limit for this mission is quite high, and you can get a good score if you're careful not to lose any squads.

Start by taking the beacons in the center. Advance carefully and kill off synapse creatures, especially ranged ones (Zoanthropes and barbed strangler Warriors). Cyrus with his High Power Shot is very handy for this, and he can use Infiltrate & Demolition Charge for the Hive Nodes as well. There are swarms of Hormagaunts and Rippers that you can scatter with To Victory! and mop up with Avitus – charge and retreat to draw them in his range if necessary.

There is usually a Carnifex by the Imperial Shrine; it can be tough for an anti-infantry team. You can use a Signum artillery strike on it (just one, it will regenerate if you wait for a second one), dump your grenades/demo charges on it, hit Rosarius immortality, charge it with your melee unit(s) and then concentrate all fire on it.

When the map is cleared, go north for the Warrior. He will jump around and try to engage your ranged squads; keep him occupied with a melee unit and keep your ranged units scattered so he can't mess up several at once. Dropping turrets around the arena can help to whittle him down and also tie down the low-level swarms he summons. There's a beacon quite near so don't be afraid to retreat if necessary. He's not a very tough boss, however, so you should come through fine.