The Reaver Battle Titan is a Titan Unit for both the Imperial Guard and Space Marines.
The Reaver Battle Titan is above the Warhound Titan and below the Warlord Titan. It's slower than the Warhound but makes up for this by having longer range, more armour and shields and deadlier weaponry. The Reaver excels at supporting offensive actions. It's Missile Barrage ability can tear an enemy force apart and can do severe damage to a base while it's primary weapons can destroy practically anything. It's a good idea to use it against massed enemy forces, bases and other titans. A Reaver can take on a Warhound Titan and even a fellow Reaver but it will need help against a Warlord or an Imperator titan. Contrary to it's icon, the Reaver doesn't have a power fist and neither is it good in melee so you'll need to support it in the event something attacks it in melee.