Simulacrum

A Simulacrum (, plural: simulacra) is a near-perfect robotic clone of an actual person introduced in. Created by Elysium, the simulacra are indistinguishable visually from the original person, and are capable of inheriting their personality, voice and fighting style.

Supreme Leader Rufus Albarea
A Rufus Albarea simulacrum interrupted Crossbell's independence signing in a bid to declare himself the Supreme Leader of the Crossbell Unified Nation, being created from the aspirations that Rufus had prior to his defeat in. He initially defeated the entire SSS on his own, and afterwards, assumed control of the city with the help of his forces, the Black Guard, and the assistance of the other Simulacrum created. He later fought alongside a brainwashed Ilya Platiere against the unified teams, before being ultimately defeated and partially bisected by the true Rufus.

The Supreme Leader understood that he was an imitation, but had a desire to surpass the original. When he offered the original the chance to join him, he declined, but acknowledged that his old self would've likely accepted, showing how the original Rufus grew compared to the simulacrum.

Emperor
A simulacrum of the high-ranking member of Garden known only by his codename as the "Emperor" appeared to assist the Supreme Leader, and was seen observing his first speech in Crossbell. Unlike the other people whom a Simulacrum was made based off of, the original Emperor had been deceased by the time of the simulacrum's first appearance; he was killed at the hands of his former subordinates and defected Garden members, Swin Abel and Nadia Rayne, during the events of Three & Nine.

The simulacrum wielded copies of the Monarch's Regalia that the original used in combat. Like the original, he was defeated by his former subordinates with the help of their team. Not long after being defeated, the simulacrum transformed into a large monster; it attacked the team at Aurochs Fort before being destroyed a final time.

Judging by his reactions to Nadia's analysis of him and F. Novartis's words, this simulacrum did not appear to be initially aware that it was a clone. However, it desired to surpass the original once it realized this truth.

Arios MacLaine
Multiple simulacra of Arios MacLaine were created to aid Supreme Leader Rufus in his plans. In contrast to the other simulacra, the ones of Arios are imperfect imitations of him; they behave erratically and out of line with the original's noble character, and do not appear to be able to replicate his strength as the real Arios is shown destroying multiple with ease. The simulacra were fought by Rean Schwarzer's team in the Nord Highlands, and Rufus's team in Crossbell.

McBurn
F. Novartis somehow managed to create a simulacrum of Ouroboros's most powerful Enforcer, McBurn, whom he had battle against the SSS in one of his factories. Novartis was disappointed to see the clone lose its arm after unsuccessfully trying to transform into McBurn's true form; despite being able to successfully use a replication of the Angbar, McBurn's Divergent Laws weapon, it could not replicate the power of his otherworldly form. It perished when the factory Novartis summoned it in exploded, but not before warning Novartis that he should make sure the true McBurn doesn't find out.

It remains unknown how Novartis was able to make this simulacrum.