Guren SEITEN Eight Elements

The Guren S.E.I.T.E.N. Eight Elements (紅蓮聖天八極式, Gurenseitenhakkyokushiki) was upgraded from the Guren Flight-Enabled Version after Kallen and the Guren were captured during a battle with the Chinese Federation and turned over to the Holy Britannian Empire, after which Lloyd was given access to the Guren. Much like Rakshata and the Shenhu, they got carried away in their modifications and made it too difficult for ordinary people to pilot properly. The Guren S.E.I.T.E.N. Eight Elements was recaptured by the Black Knights, but its modifications were only 60% complete when it was piloted by Kallen Kōzuki.

Design and development
The Guren now uses the Energy Wing similar to that of the Lancelot Albion, but with four energy "feathers" instead of three. The feathers are capable of functioning as blades, shields, and projectiles. The system allows the Guren to move at blinding speeds, such that it appears to be little more than a purple blur in flight. Its radiant wave surger arm has gold highlights on the fingers and forearm, and has been upgraded from its previous form. It can be fired like a Slash Harken, with a Harken Booster for controlled flight. The arm continues to function while separated from the main body. While the RWS can fire at long-range as in the Flight-Enabled version, the S.E.I.T.E.N. is also capable of launching a disk-like energy projectile. It also is newly equipped with two Slash Harkens attached to its shoulders.

All of the Guren's original functions are retained and upgraded. The regular short-range radiation burst can block a Hadron Cannon blast, while the hand can crush energy shielding without the aid of the emitter. The Guren's fork knife is also upgraded, having been retrofitted with MVS capability and doubled in length. The power of the MVS is more potent than most MVS weaponry, as shown by its purple coloration, as opposed to the typical red. The knife is used to cut through the Lancelot Conquista's MVS swords and shatter the Percival's MVS Particle Lance.

Additional armor has been added to the knees and ankles, the antennae have been extended and enlarged, giving the appearance of giant ears. The torso has been remade, with the orange section extended further outward and a pair of green jewels featured prominently on the front. Its namesake comes from its operation system, the Superlative Extruder Interlocked Technology Exclusive Nexus (S.E.I.T.E.N.) Eight Elements.

According to Lloyd, a capable devicer (like Kallen) can destroy eighth-generation knightmares or below even at 60% of its total output. "With a capable devicer, even at 60% output that thing can cut the other Knightmares to ribbons!".

Operational history
The Guren S.E.I.T.E.N. is first seen after Kallen is freed from prison during the second battle of Tokyo where it is shown to her by her rescuers. Despite being supposedly being made too difficult to pilot by Lloyd's tinkering, Kallen manages to pilot the upgraded Guren and with it quickly turns the tide of the battle, destroying countless Britannia Knightmares as well as single-handedly defeating the Valkyrie Squadron, Knight of Ten Luciano Bradley in his Percival and severely damaging the Lancelot Conquista to the point that Kururugi's "Live" command activates and forces him to use F.L.E.I.J.A.. Kallen and the Guren escape the blast however and retreat with the rest of the Black Knights.

The Guren's final deployment is during the Battle of Mt. Fuji. During the battle Kallen attacks the Avalon with the Guren in an attempt to kill Lelouch but is stopped by C.C. in the Lancelot Frontier. After quickly defeating C.C. Kallen is soon challenged by Kururugi in his Lancelot Albion and the two begin an intensive duel. During the fight, both the Guren and Lancelot ran out of sufficient amount of energy to power most of their systems, including the Energy Wing, forcing them to battle aboard the Damocles. After more intensive fighting both Knightmares delivered a last blow, the Lancelot was completely destroyed and the Guren lost its arms and head and plummets from the Damocles after Kallen falls unconscious, but is caught by Gino in a damaged Tristan Divider. It is not shown what becomes of the Guren following the Zero Requiem though presumably it was returned to Rakshata.