Yggdrasil (Sand Cruiser)Edit
The first Yggdrasil is an enormous sand submarine stolen from Aveh and operated by Bartholomew Fatima and his crew of Sand Pirates. It includes living quarters, a lounge with a bar, and a Gear Hangar. Fei Fong Wong meets Bart and acquires use of the Yggdrasil for travel and shopping shortly after leaving Lahan.
Yggdrasil II (Submarine)Edit
After the original Yggdrasil sinks, a second nearly identical ship is discovered beneath the sands of the Ignas desert. This Yggdrasil is capable of moving on water, as well as in sand. This allowed Bart, and later the rest of the party to explore a vastly wider area of the world than previously possible. Because it is the second Yggdrasil which Bart has commanded he names it the Yggdrasil II. The Yggdrasil II is equipped with special surface-to-air missiles, unsurprisingly dubbed "Bart Missiles" by Bart. Bart uses them to shoot down the Goliath, but he is unaware that his friends are aboard the Kislev airship when he opens fire. The ship is later pushed to its limits when the party mounts a daring assault against the submerged Sargasso Gate. Finally, when the party manages to reach Shevat by going through Babel Tower, the Yggdrasil II is brought Shevat itself and is fitted with a special extension that allows it to fly.
Yggdrasil III (Airship)Edit
After the party reaches Shevat, the Yggdrasil II is adapted to be able to fly and is renamed to the Yggdrasil III. The attachments that enable the ship to fly, as well as the ship itself were designed by Roni Fatima, Bart's ancestor and were stored away in Shevat for safe keeping until the time was right. With the Yggdrasil now flight capable it could no longer float in the water or on the sand, however its operating range had increased dramatically. With the Yggdrasil III in their possession there was literally nowhere on the planet that Bart, Fei and their friends could not go, except Solaris.
Nortune Administrative Building (Yggdrasil IV)Edit
A battlecruiser that transforms into a massive gear with extremely powerful attacks. It was found by Roni Fatima and was disguised as the Nortune Administrative Building (hence the structure's awkward shape). When the Yggdrasil III docked with the structure it activated its true systems, left dormant for over 500 years and allowed it to transform into its true form. The Yggdrasil IV, so named by Bart was meant to be a symbol of friendship and co-operation between Aveh and Kislev and required a piece of technology from both countries in order to properly activate it. The deeper meaning of the machine was lost with time and even further muddled by the war, however when Aveh and Kislev joined together in peace its true purpose was unlocked again.
Like many things in Xenogears, the Yggdrasil IV is an obvious nod to a pre-existing anime archetype. It is designed very similar to the Macross from the anime of the same name. It is also introduced in its one and only battle as the Super Dimension Gear Yggdrasil IV. The Macross is described as a "Super Dimension Fortress". In addition the Yggdrasil VI's head bears a strong resembelance to the head of the VF-1J, piloted by the series protagonist in SDF Macross.