“The true soul of a person shows in the hard choices they make. What you decide when the chips are down and time has run out... That is who you truly are!”
- ― Will
During a meeting with Arkarium, Hilla and Damien, they encircle a sealed Rhinne, gloating in their success. Arkarium says that Rhinne's powers are now his and Hilla asks Will if Rhinne is enjoying the dream Will gave her. Will says "Mirror World is no dream, it is a terrible reality".
Mirror World is a place where Will used a bit of Rhinne's power to trap Rhinne, but Rhinne then shed a tear and created her successor so Will split her child into two, a boy (Alpha) and a girl (Beta) and sealed away one and kept the other one for their own use. Will is the main antagonist of Zero's storyline as Will created the Shadow Knights and tried to take all of Rhinne's Goddess Teardrops and get back Nine (Alpha) to the Shadow Knights.
After Fang, a member of the Shadow Knights warns Nine about Will's true intentions, back when Nine was known as Eight, Eight slowly starts having suspicions, but whenever he gets close, Will and his Shadow Knights always erase his memories, and changes his name to distinguish the number of time he had been brainwashed.
Nine found the location of the Umbra Temple and finds a girl chained up. He frees her but Will confronts him. He easily overwhelms Nine, since Nine has no idea of his Spider-like abilities, but the children of the transcendent activate their abilities and warps themselves to another location. Will cannot follow them into their dimension and so continues his plans.
The two children face Will a couple of times. One of those times, Will says that one of them is tainted so they can never be true transcendents. Another time, he reveals that he had been draining Rhinne's powers and orders a manipulated Rhinne to attack her children but she frees herself and attacks Will. Will flees the scene.
After Will is bested in their final confrontation, he flees and is not seen again until the events of Esfera.
The player meets with a squad sent to assist them: Ollie, a member of the Cygnus Knights Striker squad who was sent to protect the player; Shubert , a technician assisting with communication to Ereve; and Melange , a witch sent from Pantheon to create a portal between Mirror World and Ereve. While on a flying ship traveling through Esfera, a masked individual appears and destroys the ship, scattering everyone. Ollie and the player are left together while Melange and Shubert are elsewhere. Ollie tells the player that they should try to find the others, and while on the search for materials, Will appears for the first time. When the player meets Will, they don't know who he is (unless you are playing as Zero). Will briefly exposes his plans to the player about using Tana (who has become Aeona, the Transcendent of Light of Grandis) for a ritual involving the Black Mage, who doesn't simply want to destroy everything, but to create an entirely new world. However, Will's initial plan was foiled earlier by a mysterious force attacking Will mid-ritual. As a result, Tana fell deep into Esfera's waters.
The group discovers that Will is not at his full power because of Tana's influence in Esfera. After battling Will's spider minions, they receive help from one of Tana's own minions, an executioner, who knows that "the enemy of my enemy is my friend", and therefore assists the group in finding Tana. The group eventually finds Tana's location, and Ollie goes underwater to rescue her. Once they reach the surface, Ollie's bandages fall off, revealing a spider mark left by Will. This enrages the executioner, leading to a group of them attacking Ollie, believing her to be working for Will. The player then defeats the executioners to protect Ollie, but this accidentally weakens Tana. Will then appears, attacking the player and their allies. Shubert, only able to teleport one person back to their base, is told by the player to teleport Ollie instead of Tana. Will comments at how you risked the fate of the entire world to save Tana, also remarking that you were the only obstacle the Black Mage had to deal with, making it natural for others to be sacrificed along the way. A masked person appears right before Will drops the player into the water, leaving them to choose between saving the player or Tana. The masked person saves you as Will flees, and is revealed to be the one who stopped the ritual earlier telling the player "In order to stop him…. the great adversary is needed", and sends you back to the base.
Back at the base, the player learns that Ollie's spider mark is a poisonous curse, leaving Ollie with little time, as it can only be reversed by the caster, Will. The only way to reach Will is through a mirror portal, and the player is prepared to deal with any of Will's traps. After travelling through a reflection of the Radiant Temple (the real temple is where Tana and Aeona once lived), the player confronts Will by entering yet another mirror within. Will resumes the ritual and tells the player that Tana must be killed in order to stop the ritual. He reveals that a person's true self is determined at the moment of choice, and then fights the player directly.
Will reverses the curse after being defeated, but also tells the player to kill Tana to stop the ritual. However, the player hesitates at the last moment out of guilt and empathy for Tana, who has suffered for many years. Tana is then absorbed by the Black Mage, giving him the powers of two Transcendents. Will is surprised by their hesitation, even asking them if they know what they are doing. He admits his admiration for the player, but says he cannot let the player, who is the Black Mage's greatest adversary, live. He escapes after unleashing a horde of spiders to attack the player, but Melange creates a gate for Ollie, the Chief Cygnus Knights, and Neinheart to travel through and rescue the player. The player regrets being unable to stop the ritual, but Neinheart consoles the player by saying that knowing the Black Mage's plan is an achievement in and of itself, and that now they are ready for the real battle. Melange recovers Will's book that he dropped during the chaos and takes it to further study it.
Afterward, Will has retreated into the deepest part of Mirror World, lamenting about being unable to defeat the player for good, but is glad that the Black Mage's plans have succeeded, and awaits the creation of the new world. However, the Masked person followed him there, and proceeds to fight Will.
After the defeat of the Black Mage, Will's unconscious body is seen drifting around the seas of Esfera. He is discreetly taken and kept locked up in a jail cell deep in Ereve. Neinheart voices his concerns about keeping a dangerous convict near the Empress, but since Will is now powerless with the Black Mage dead, it should not be a problem anymore. Will was the only one of the Black Mage Commanders to know all about the Black Mage's plans and followed him to the end, so he is very knowledgeable in the world of Transcendents, so his knowledge is paramount in the Alliance's battle against another Transcendental Threat. Will had remained unconscious until recently, where he was being interrogated by Grendel the Really Old, and is suspicously cooperative. He knows that Grendel is well aware of the Black Mage's intentions, and gave him a core filled with the Black Mage's thoughts. This sends Grendel into a haze and disappears into the Arcane River. If talking to Zero, he says that although he himself is a very patient person, he cannot wait for what comes next.