Guren SEITEN Eight Elements

After Kallen and the Guren are captured during a battle with the Chinese Federation and turned over to Britannia, Lloyd is 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. In their care, it is upgraded into the Guren SEITEN Eight Elements (紅蓮聖天八極式, Guren S.E.I.T.E.N. Hakkyōkushiki lit. Crimson Lotus Heavenly Eight Extremities Type). The Guren SEITEN Eight Elements is stolen by the Black Knights, but it only had 60% of development 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 wings can also serve as Cutting Weapons, Shielding Weapons and Ranged Weapon. 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 significantly. It can be fired like a Slash Harken, and has a Harken Booster for controlled flight and can be a sharp Battering Ram Like Drill. The arm still functions when launched as such. Its original functions are retained and far more potent: the ordinary radiation burst can block a Hadron Cannon blast with seemingly no effort and the hand can crush energy shielding without the aid of the emitter. It is also capable of firing disk-like radiation projectile. The Guren's fork knife is also upgraded, having been retrofitted with MVS capability and made about twice as long. Its MVS (which is colored purple as opposed to the usual red) is evidently more potent than normal versions, as it can cut through the Lancelot Conquista's MVS swords.

Additional armor is also present on the knees and ankles. The antennae have been extended and enlarged, making them appear to be giant ears. Its chest is completely different, with the orange part extended further and a pair of green jewels featured prominently on the front. Its namesake comes from its operation system, which is Superlative Extruder Interlocked Technology Exclusive Nexus (S.E.I.T.E.N.) Eight Elements. It also is equipped with two Slash Harkens attached to its shoulders.

According to Lloyd, a capable devicer (like Kallen) can destroy eighth-generation knightmares or below even at 60% of its total output.

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 Suzaku'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 Suzaku 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 it's arms, 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.