The origins of Lieu were coming from one of Oguma's experiments. However due it's unstable state, Oguma decided to abandon Lieu inside the North Pole's Alator. In 2030s after South Pole's Alator were activated in favor of Lugus, it inadvertently also activated North Pole's Alator which resulted the awakening of Lieu causing it to travelling towards South Pole's Alator. After Lugus is almost defeated, Lieu somehow managed to reach South Pole's Alator much to the surprise of Oguma, Marco, Eri, Tarma and Fio. Lieu then unleashed a reddish fluid-like flesh towards Lugus consuming it and trapping the Regular Army cadets inside. Rumi Aikawa then drops the SV-001 in order to destroy Lieu. Once defeated, the Lieu starts collapsing with Marco, Eri, Tarma and Fio escaping via a Regular Army Helicopter while Oguma and his henchmen stay behind. Oguma is then consumed by Lieu causing it to be destroyed in a huge energy blast.
He shoots laser with many eyes (not the main eye), some eyes can be destroyed either dropping materials, weapons, health packs or gas tanks. After a few moments, it grows 2 arms with one eye in both arms. The eye acts similar to the previous eyes. If you get close to the arms, it will slash you with its finger. When one arm is defeated, Lieu's main eye will be exposed. Should both arms be defeated, it will give you extra time. At this point several faces start raining the area. If the player doesn't attack the remaining arm, it will retreat and the face will try to eat you. Several arms will then try to punch you before a foot finally falls from above trying to crush you. After dealing enough damage to the Lieu, it will endlessly scream as the faces keep falling from above.
- The smaller faces have ears while the main big face doesn't.
- The small eye pods bear similarities with the Unknown Alien's stage.
|Metal Slug 3D|
|Major Characters||Marco Rossi | Eri Kasamoto | Tarma Roving | Fio Germi|
|Supporting Characters||Rumi Aikawa|
|Antagonists||Donald Morden | Allen O'Neil | Oguma|
|Organizations||Regular Army (Peregrine Falcons | S.P.A.R.R.O.W.S) | Rebel Army | Oguma Corporation|
|Bosses||M-3 Rocket Launch Support Van | Mosque Artillery | Spider-Bot | Underground Cruise Missile | Morden's Battleship | Morden's Castle | Allen O'Neil | Lugus | Lieu|
|Weapons||Heavy Machine Gun | Rocket Launcher | Laser Gun | Shotgun | Flame Shot | Enemy Chaser | Iron Lizard | Super Grenade | Drop Shot | Double Machine Gun | Grenade | Fire Bomb | Monolith | Sniper Rifle | Smoke Bomb|
|Slugs||SV-001 | Slug Gunner | Slug Flyer | Slug Mariner|
|Missions||"Start From Mountain Village" | "Be Headquartered in the City" | "Desert Town" | "Coal Mine Mark" | "Coal Underground Ruins" | "Atmospheric Discharge" | "Break the Barrier" | "Sink Under the Waves" | "The South Pole" | "Climb the Tower" | "Out of Control"|