The Forbidden Land, Eureka Hydatos is a 
Field operation and the fourth and final addition to The Forbidden Land, Eureka. It is unlocked by completing the story objectives within 
The Forbidden Land, Eureka Pyros. Leaving the icy fields and volcanic caves, the zone is set in the wetlands at the base of the headquarters of the Students of Baldesion.
Story[]
Following the destruction of the ward on the eikon Eureka by Ejika Tsunjika, the Eureka expedition has managed to reach the plains at the foot of Baldesion Headquarters and set up camp. Krile begins to make preparations to restore the ward and journeys around the region with the Warrior of Light to several aetheric confluences to redirect the flow of aether.
Eventually, she is able restore the aetherial bridge to the headquarters and the duo journey inside. There they discover Eureka, an elaborate cube shaped being, sealed inside a final ward.
Browsing around Galuf's displaced notes, they uncover several facts: that Eureka is an eikon from the age of Allag with the ability to create anything a user wishes for, be it weapons or even a new mother crystal, that the user is selected by a special avatar of Eureka in the form of a hooded figure and thus the current user is Ejika, and that the weapons, including the Zantetsuken, created by Eureka are extensions of Eureka's eikonic nature and thus can enthrall their wielder.
They also learn that the Ascian Emmerololth had uncovered Eureka's existence on Val and attempted to obtain it, prompting Galuf to enact a failsafe to dump the entire island into the Lifestream in an effort to destroy them. This however, allowed Eureka to "pilot" the island out of the Lifestream to its current location in the Glass Ocean, with the fate of Galuf and the other surviving Students left unknown.
Ejika soon appears with Eureka's avatar, which encourages him to destroy the final ward and claim the power he has long desired, however the Warrior realises that Ejika is not in fact enthralled, and coordinates with him to take the sword gifted to the scholar and use it to destroy the avatar.
With its defeat, Ejika debriefs with his companions about how he realised the nature of Eureka and that he allowed the first ward's destruction to bring him closer to the original eikon. He claims that they have been given a chance to do what Galuf and his companions could not: to destroy Eureka outright.
As the eikon's currently selected user, Ejika plans to command it to send both it and himself directly into the lifestream, where it would be torn apart by the flow of aether since the ward keeping it sealed would no longer protect it. Krile objects to this plan, as she does not want to lose another of her companions, and believes Eureka should be sealed until they discover a safer way to destroy it, following the footsteps of her grandfather. Having come to an impasse, the two turn to the Warrior to make the final decision.
Weather[]
Eureka Hydatos' climate may exhibit any of the following weather conditions:
| Weather | Frequency or conditions |
|---|---|
 Showers
|
22% |
 Thunderstorms
|
22% |
 Snow
|
22% |
 Gloom
|
22% |
 Fair Skies
|
12% |
 Umbral Turbulence
|
Occurs when  I Don't Want to Believe or The Baldesion Arsenal are active.
|
Activities[]
FATEs[]
| Name | Elemental Level | Location | Time limit | Objective |
|---|---|---|---|---|
| Description Spawn conditions (if any) | ||||
 I Ink, Therefore I Am
|
50-53 | The West Val River Bank (x11 y25) | 30 minutes | Defeat Khalamari. |
| Perhaps having seen one too many cephalopods harvested by expedition members for later salting or frying, a particularly large specimen has taken to brutalizing any who so much as lick their lips in its vicinity. As such, those who refer to Khalamari by its nickname are advised to do so quietly.
Spawn conditions:
| ||||
| Drink Me
|
50-53 | The Val River Source (x14 y21) | 30 minutes | Defeat Haokah followed and its minions. |
| As a brief respite from their mischief-making, Eureka's happy bunnies have opted to take refreshment at a nearby stream. Alas, it is a simple matter for victims of their shenanigans and creatures to whom they look like tasty snacks to find them at such a popular watering hole, and they will require saving once again. | ||||
| From Tusk till Dawn
|
51-54 | The West Val River Bank (x10 y17) | 30 minutes | Defeat the stegodon. |
| Even be it ages old and half-fossilized, a stegodon never forgets its enemies─those who hunt its kin looming large among them in its memory.
Spawn conditions:
| ||||
| Bullheaded Berserker
|
52-55 | The West Val River Bank (x7 y22) | 30 minutes | Defeat Molech. |
| Gruesome was the campaign brutal Molech and his band waged across western Hydatos, until their sole weakness─allergies─brought it to a screeching halt. With the pollinators responsible dead, however, swift and decisive action will be necessary to thwart his reign of terror.
Spawn conditions:
| ||||
| Mad, Bad, and Fabulous to Know
|
53-56 | The West Val River Bank (x6 y14) | 30 minutes | Defeat Piasa. |
| If anything can be said to command more pity than the flightless bird, it surely is the flightless flock being hacked to bits by uncaring adventurers' blades. Thus is pity the charitable motive ascribed to Piasa by expedition naturalists─though some have seen it admiring the contrast of blood against its colorful plumage.
Spawn conditions:
| ||||
| Fearful Symmetry
|
54-57 | The West Val River Bank (x7 y26) | 30 minutes | Defeat Frostmane. |
| Having slain his way through the felines of his home continent, besting each in single combat to hone both muscle and instinct, Frostmane struck out to seek fiercer tigers on which to sharpen his claws. But if his chosen prey is absent, its slaughterers will do.
Spawn conditions:
| ||||
| Crawling Chaos
|
55-58 | The East Val River Bank (x25 y16) | 30 minutes | Defeat Daphne. |
| Wisps of blood curl across water's surface, drawing Daphne with its sweet scent. Though the face that she, he, it wears be not its true visage, nor Daphne its true name─merely a whisper that comes unbidden to the minds of those who gaze upon it─remember: some truths are better forgotten.
Spawn conditions:
| ||||
| Duty-free
|
56-59 | The East Val River Bank (x28 y23) | 30 minutes | Defeat King Goldemar. |
| Guided by the sweet symphony of suffering souls, King Goldemar has emerged from the void with an eye toward trade with our realm. Lord of smithies he may be, but accept neither his wicked works nor his curse-forged coin.
Spawn conditions:
| ||||
| Leukewarm Reception
|
57-60 | The East Val River Bank (x37 y27) | 30 minutes | Defeat Leuke. |
| After consuming a great many nutritious voidsent with its assorted jaws, Leuke proceeded to set its sights on attracting a veritable army of pollinating insects so that it might grow even larger. It is evidently not best pleased to see their ranks thinned.
Spawn conditions:
| ||||
| Robber Barong
|
58-60 | The East Val River Bank (x32 y24) | 30 minutes | Defeat Barong. |
| Despite being more earthfire than beast at this point, the lord of lionkind still feels kinship with his subjects. He will see them avenged, even should all the world burn to ash.
Spawn conditions:
| ||||
| Stone-cold Killer
|
59-60 | The East Val River Bank (x36 y13) | 30 minutes | Defeat Ceto. |
| Ceto's handmaidens─and only they─are as children to her, so it ought to come as no surprise that their murder would set her shaking, slashing, and spearing with rage. Other things one should avoid being surprised by include the reach and lethality of her assorted limbs.
Spawn conditions:
| ||||
| Crystalline Provenance
|
60 | The Crystal Dragon's Bloom (x32 y19) | 30 minutes | Defeat the Provenance Watcher. |
| Upon attempting to clear loose crystals away from an unusually large formation, expedition scholars were intrigued and alarmed─mainly alarmed─to discover a live dragon. None know whence it came or wherefore it is so full of rage...though one naturalist did admit to having poked it in what might have been its eye.
Spawn conditions:
| ||||
| I Don't Want to Believe
|
60 | The Val River Source (x26 y29) | 15 minutes | Defeat Ovni. |
| A source of major aetherial disruption throughout Eureka has been found nestled amidst the isle's protean currents. Though the creature's nature has yet to be identified, its capacity for destruction is clear.
Spawn conditions:
| ||||
| The Baldesion Arsenal: Expedition Support
|
60 | The Val River Source (x19 y28) | 15 minutes | Defeat Tristitia and the phuabo. |
| Despite being sealed in the tower, one of Eureka's transcendent weapons has managed to forge creations of its own by transferring to each a portion of its essence. Needless to say, all must be eliminated.
Spawn conditions:
| ||||
| Conquer the Baldesion Arsenal | 60 | The Val River Source (x21 y31) | 25 minutes, +20 minutes upon defeating each boss | See The Baldesion Arsenal.
|
| "In the course of his investigations, Master Ejika made an unsettling discovery. When the founders unearthed Eureka, it had by then forged a fearsome arsenal of weapons. The founders made it their mission to locate these arms, which they sealed away in the headquarters' upper level─a place dubbed the Baldesion Arsenal. For years the weapons lay dormant, but the recent disturbances on the isle may have caused them to awaken. To become sentient. Now, according to Master Ejika's report, an arcane ward prevents access to the Baldesion Arsenal. However, by exploiting an anomaly in the Lifestream which occurs under certain weather conditions, it is possible to teleport inside. And here is where you come in."
Spawn conditions:
| ||||
Etymology[]
Eureka is an interjection used to celebrate a discovery or invention. "Eureka" comes from the Ancient Greek word εὕρηκα heúrēka, meaning "I have found (it)".
