Olisi

"Lesovikk said Karzahni can show you alternate events--usually horrifying ones, intended to terrify you. [...] what if he showed you a future--or a past--that you wished for? And what if you wanted it so much...that you stayed trapped in that vision forever?"

- Sarda

The Kanohi Olisi was the Mask of Alternate Futures.

History
The Great Beings created the first and only Olisi, which Karzahni received after he failed to defeat his brother Artakha for the right to wear the Legendary Mask of Creation. Karzahni wore the Olisi for the next 100,001 years, until he traveled to Mahri Nui and was exposed to the Pit Mutagen. This then fused the Olisi to his face, although he was still capable of accessing its powers.

After Makuta Teridax (in the body of Maxilos) destroyed Karzahni's sanity, Karzahni used his Olisi's power to trap Toa Lesovikk in a vision of an alternate timeline where his team had never died. Despite the lure of the dream and initially believing it, the Toa of Air eventually realized that he was trapped in an illusion. This realization was enough to allow the him to force his way out of the Olisi-created hallucination.

After Teridax in the body of the Great Spirit was killed by Mata Nui, Mata Nui used the powers of the Prototype Robot and the Kanohi Ignika to unmutate those affected by the Pit Mutagen. Karzahni was included in its range of effect, reversing the effects of the mutagen upon himself and the Olisi. Karzahni later died in a suspicious manner upon the newly-reformed Spherus Magna, leading to his body falling off a cliff. The Kanohi Olisi was broken and destroyed upon his impact with the ground.

Powers
The Kanohi Olisi gave its user the power to project a mental vision of an alternate timeline or a possible future into their and one or more being's minds at once. The user could use their thoughts or thoughts of the victim(s) to create the vision; the user will also share in the created vision. While the user could place a vision in a target's head and leave it alone, this made it easier to free oneself from the vision. Karzahni tended to activate the Olisi's power through an energy blast aimed at his target(s). It seems that the user does not control exactly what is seen, as several times Karzahni gave visions of events he could not know about. Rather it seems that he simply dictates whether it will be a pleasant vision or a nightmare, and the victim's own mind and memories create the details.

Example Usages

 * Great: In BIONICLE Legends 2: Dark Destiny, Karzahni used the Olisi to give the Ta-Matoran Jaller a vision of an alternate timeline where he had not saved Takua during their searching for the Toa of Light. Karzahni later used the Olisi again to create a vision of a possible future of what would happen if Mata Nui died.
 * Great: In Dreams of Destruction, Karzahni planted a vision in Lesovikk's mind of an alternate version of his past. However, since Karzahni did not continually focus on the Toa, Lesovikk was eventually able to break out of the mental illusion.

Great

 * Karzahni - Formerly; now deceased.

Trivia

 * In the Finnish language, "olisi" means "it would be" or "it would have been", which fits with the Kanohi's ability to show events that "could be" or "could have been".

Olisi