Long ago, prior to the events of the game, the Bionis fought a vicious battle against its mechanical counterpart, Mechonis, chopping off its left arm in the process, before both titans would gravely wound one another and enter a dormant state.
While most from Bionis were taught that the Great Battle was only between the titans themselves, the Data Centre in Agniratha reveals that countless Telethia were sent to devour life on Mechonis, and nearly succeeded.
Several millennia later, the Bionis would awaken once again, after Zanza re-emerged from Shulk's body in Mechonis Core. With little effort, the Bionis would conjure its Monado once again. A single stroke of the blade would suffice both to break Sword Valley in half and slice the Mechonis' core in half with extreme precision. Fiora and Meyneth would briefly stop the Bionis' assault by confronting Zanza directly, but Zanza easily claimed victory, killing Meyneth and taking her Monado for himself. Zanza would then transport himself to Prison Island and would sink it into the Bionis' head, causing an extreme spike in atmospheric ether levels on the titan's upper regions, transforming every pure-blooded High Entia on the upper Bionis into Telethia. Only those with mixed heritage or far enough away from Eryth Sea were spared from this.
With the destiny Zanza laid out for the High Entia fulfilled, the Bionis would attempt to annihilate Shulk and company aboard Junks, only for the Mechonis to shield the vessel under Egil's direction. However, the Bionis proved strong enough to break off the Mechonis' other arm barehandedly. Monado in hand, the Bionis would bring its sword down for the final time, killing Egil and leaving the Mechonis in ruins.
The final attack from Egil proved invaluable, however, as it provided an entryway into the Bionis' Interior after Shulk had recovered from his brush with death. This allowed them all a direct path both to Prison Island, and the Memory Space Zanza had retreated to. After Zanza's death, and Shulk's decision to reject godhood, the Bionis would collapse, partly sticking out of the ocean. Colony 9 would remain on the shore of the sea near the Bionis' head, with other locations unseen but presumably intact to varying degrees.
Following the collapse of the Bionis, the Bionis' Shoulder remains suspended in the air, thanks to the shoulder's high geological content of Hover Stone. Shulk and Melia travel to the Bionis' Shoulder so that they can reach Alcamoth.
Xenoblade Chronicles 3
Sometime following the events of Future Connected, both Bionis and Alrest learned of one another's existence, and the impending calamity of their worlds' Intersection. Both worlds would construct half of Origin, with the intent of letting both worlds and the lives within survive this cataclysm. However, rather than annihilate and dissolve into light as predicted, Origin, hobbled by the coalescence of Moebius, jumbled both worlds together, freezing them in an eternal present.
Various parts of the Bionis can be seen scattered across Aionios. The head of the Bionis can be seen as part of Erythia Sea, and other extraneous parts can be seen off in the distance; the titan's left arm connecting Cadensia to Upper Aetia, the upper portion of the right shoulder near the head. The Bionis' leg has been oddly bifurcated; Gaur Plain and the lower half of the thigh fusing with Gormott in Aetia.
After Z's defeat and Origin's reactivation, Bionis (and presumably Mechonis) and its denizens would be restored.
In the Cent-Omnia Region of Aionios, Raguel Lake has fused with parts of Tantal, and Colony 9 has been completely displaced from its position relative to the Bionis' head, with Gotrock Oracle Ruins transplanted right next to it. The Black Mountains are also comprised partly of Bionis remnants; combining Tantal, Valak Mountain, and Prison Island.
Following the defeat of Alpha, Origin plummets into Aionios, completely destroying the Cent-Omnia region.
Areas on the Bionis
- Colony 9
- Tephra Cave
- Bionis' Leg
- Colony 6
- Ether Mine
- Satorl Marsh
- Bionis' Interior
- Makna Forest
- Frontier Village
- Eryth Sea
- High Entia Tomb
- Prison Island
- Valak Mountain
- Bionis' Shoulder
Areas of Xenoblade Chronicles and Future Connected
|Colony 9||Colony 9 • Tephra Cave|
|Colony 6||Bionis' Leg • Colony 6 • Ether Mine|
|Central Bionis||Satorl Marsh • Bionis' Interior • Makna Forest • Frontier Village|
|Upper Bionis||Eryth Sea • Alcamoth • High Entia Tomb • Prison Island (II) • Valak Mountain|
|Mechonis||Sword Valley • Galahad Fortress • Fallen Arm • Mechonis Field • Central Factory • Agniratha • Mechonis Core|
|Future Connected||Alcamoth • Bionis' Shoulder|
|Other||Junks • Land of Challenge • Memory Space|