|"Wow! That's some pretty classy gear!"|
–William admiring his sword in "Final Round".
In the episode Final Round, William primarily uses the Zweihänder to deliver slow but powerful blows, defeating several Creepers with a single hit. For defense, William is able to reflect lasers at monsters by using the sword.
Since being possessed by X.A.N.A., the Zweihänder gains the ability to charge up and then release energy in the form of silver waves, which are also rather slow to execute, but exceptionally strong nevertheless.
Code Lyoko Evolution
After being released from X.A.N.A.'s control one year ago, the Zweihänder receives several upgrades from X.A.N.A. (which also includes the ability of Super Smoke). With William's increased physical strength, the sword is easier to handle, increasing his dexterity with the weapon. The Zweihänder is also heavily integrated with William's Super Smoke ability, and he is able to use the ability to make the sword vanish when not using it, or summon it directly to him if he is separated from it.
The Zweihänder is a massive sword, longer than William is tall. It has a wide, single-edged blade and a long, thin handle. The blade is silver in color and glows white when being used in combat, including while charging a wave attack. Apart from these general features, the Zweihänder goes through several appearance changes throughout the series.
While William is under X.A.N.A.'s control, the Zweihänder's handle changes from red to black, and black, root-like structures decorate the blade. There is also an Eye of X.A.N.A. near the sword's hilt. While on Earth as a spectre, the Zweihänder blade is a darker shape of grey, and the roots on the blade are red instead of black, as shown in Cold Sweat.
In Code Lyoko Evolution, the Zweihänder's appearance changes again. The handle is black with orange stripes, and there is an orange, circuit-like design on the blade. The sword is also noticeably smaller than it is in the original series.
- A Zweihänder is a traditional German sword used primarily during the early 16th century. The name translates into English as "two-hander", and like William's weapon, real-world Zweihänders are known for their exceptional size, and must be handled with both hands.
- The Zweihänder's design appears to be based on the Buster Sword from the Final Fantasy series.
- The Zweihänder was the weapon that succeeded in destroying the Core of Lyoko, and thus all of Lyoko, in the Season 3 finale.
- If one of Aelita's Energy Fields hits the eye of X.A.N.A. on the Zweihänder, its blade will glow pink instead of white, and William will be able to redirect the attack in the form of a wave; this can be seen in Dog Day Afternoon.
- William's Zweihänder has a similarity with the awakened Sparda sword from Devil May Cry, such as both swords take on a massive broadsword appearance, there are organic material embellished onto the metallish frame, and a circular spot is decorated near the handle which possess a meaning (ie: eye of X.A.N.A. marks the sword like most monster's have on their body's, and the red jewel on the Sparda sword is like the jewel seen grafted on its original user's back when seen closely.) and the sword's were at first plain white-colored swords, but held alot of great potential when shown in their transformed forms. However, with both sword's rivaling their similar strengths, abilities and looks, the Sparda sword had the trait to shapeshift its telescopic and complex parts that distinquish William's own sword.