Dickson

Dickson is a veteran of the Battle of Sword Valley a year before the events of Xenoblade Chronicles and a comrade of Dunban and Mumkhar. He is a resident of Colony 9 and act as the foster father of Shulk as well as an overwatcher for Reyn and the other residents. He claims to have found Shulk in the Valak Mountain with the Monado and his parents dead.

It is revealed once reaching Mechonis Core that Dickson is one of Zanza's disciples and raised Shulk to ensure the reawakening of the Bionis since his soul (Zanza) was reganing its power while using Shulk as a mean to achieve that.

Prior to Xenoblade Chronicles
Long before the events of the game, Dickson became one of Zanza's disciples thus granting him immortality and powers beyond what any Giant was able to achieve. 14 years before the events of the game, Dickson discovers the Monado in an unnamed icy region of Bionis, which is later revealed to be the Ose Tower on Valak Mountain. He finds the only person alive there is a very young Shulk, curled up sleeping below the Monado. Taking both the boy and the sword, he heads out.

Battle of Sword Valley
Dickson fights alongside Mumkhar and Dunban at the Battle at Sword Valley, uses his rifle/sword to fight. At first, he tries to get Dunban to retreat, considering orders to pull back to Colony 6. Dunban refuses, however and they continue to fight. Dunban later collapses under the Monado's influence, while Dickson jumps to his aid and takes a hit, taking down a Mechon as well. He and Dunban charge at a group of Mechon and survive, while Mumkhar tries fleeing to return for the Monado later on, but appears to be killed by a group of hidden Mechon instead.

Colony 9
Dickson is shown now to be a wanderer who has traveled all over Bionis, not being present in Colony 9 often. He is first seen in the Weapons development lab, reading up on Shulk's research notes on the Monado, asking what the "Hidden functions" Shulk mentions in his notes are. After their conversation, he tells Shulk to get out of the lab more and walks off. He is later seen at Dunban's house, telling Fiora where Shulk would probably have gone, but is not present when the Mechon attack but he is still seen watching Shulk and Reyn when they leaves the colony.

Colony 6
After the party is ambushed by Metal Face and his minions outside Colony 6, Dickson and Dunban arrive to aid them. This is the only occasion when Dickson can be one of the party members. However, Metal Face proves too strong even for them, and is only driven off when a Telethia sent by Alvis attacks. Dunban joins the party as a playable character after this, with Dickson as a guest leading the way to Satorl Marsh.

When he leaves the party at the end of the marsh, Dickson mutters, unheard, about not feeling good about deceiving "those kids" which is the first hint at his true affiliation. However, he returns to Colony 9 and aids them in defending against the Mechon.

Sword Valley
Dickson is present at the discussion of an allied battle force being created as the representative of Colony 9, the joining of the three sentient races of Bionis against the Mechon. He convinces Kallian of the necessity of war, and goes off to meet the party before they launch their attack on Galahad Fortress. He supplies them with Anti-Mechon weapons that he built, then leaves immediately with Alvis to return to Alcamoth. Later on, Kallian is informed of the party's disappearance after wrecking the fortress. Dickson calms Kallian by telling him he knows where the party is, before going to meet the party at the Hidden Machina Village on the Fallen Arm before they leave for Mechonis Field.

During the battle of the Allied Front, Dickson is seen piloting a Havres and attacking Faced Mechon. After Mechonis begins to move, Dickson curses Shulk and leaves the battlefield to find the party. He finds them and is in the party until they reach the Mechonis Core, where he stays behind with Alvis as the party goes to confront Egil and Yaldabaoth.

Betrayal
Dickson is revealed as one of the primary antagonists during the events at the Mechonis Core, just after the battle against Yaldabaoth and before Mechonis is destroyed. He shoots Shulk in the back as he is making a truce with Egil, incapacitating him and allowing Zanza to exit Shulk's body.

He then reveals himself as Zanza's disciple, Dickson of the Trinity, who Egil recognises from much further back, a flashback shows Dickson as a Giant, standing behind Zanza when he first attacked Mechonis.

When the party flees Mechonis on Junks, Dickson is outside waiting for them with an army of Telethia. He attacks the party with his own Telethia. The party is no match for a full group of Telethia, but Kallian appears with the Havres squadron and defends them. Dickson warns Kallian that he should be keeping an eye on his own people rather than the Telethia, and reveals Lorithia to also be a traitor and a member of the Trinity. She begins releasing large quantities of Ether, which causes the pure blooded High Entia in their Havres to transform into Telethia. However, Kallian retains some control over his Telethia form, and attacks Dickson and Lorithia, who are unable to stop him. He flies into them causing an explosion, suggesting that he sacrificed himself in order to destroy the disciples. Nevertheless, Dickson survives and appears again at the gates of Colony 6 with many more Telethia. The party is once again surrounded and outmatched, but Shulk appears at the last moment, destroying most of the Telethia. Dickson expresses surprise and annoyance that Shulk is somehow still alive, then sends his own Telethia to fight him.

After Shulk defeats it, he commands Alvis to shoulder some of the "hard work", revealing Alvis to be the third member of the aforementioned Trinity. After Alvis' Telethia is defeated, the pair escape on some Solidum Telethia. Alvis says that they will be waiting for the party, and Dickson adds that they will be on their "best behavior", to which Shulk replies, "And we'll be the best guests you ever had." Dickson acknowledges the good comeback, and once out of sight of the party he starts to shake, showing that he is scared. He laughs at himself, saying "After all these years. I never thought the day would come when I would feel fear."

Demise
When Prison Island is revisited, Dickson mocks the party, letting them chase him up through the whole tower. After the party reaches the top of the tower, he tells them that they must fight him and tries to anger Shulk by repeating that he only raised him so Zanza would have a host. However Shulk replies, "I know. And I must thank you for granting me such power. It's all down to you that I'm standing here ready for you now."

Dickson ends the conversation by reverting to his Giant form, and attacks them. Despite Dickson clearly being much stronger than the group they do not give up, and to his surprise Fiora manages to block one of his attacks. He takes this to mean she has inherited Meyneth's power, however she disagrees and claims it to be Meyneth's memories instead. Everyone begins supporting Shulk and Fiora verbally, and they manage to release Zanza and Meyneth's power, presumably left over from when the gods were inhabiting them. Dickson is momentarily stunned by this, pausing and murmuring, "It can't be. That power?!" before attacking again.

The two Homs work together to defeat him, Fiora releasing a huge wave of energy and Shulk leaping forward and slashing him deep across his chest. Dickson reverts to his Homs form, telling them that he is finished, and is going home. He also tells them that he "just wanted the power of a god," and that he would not be a martyr to stop them. The party turns away from him, Dunban lingering slightly, and leave to challenge Zanza. Dickson sits and takes a last cigar, saying, "Damn. How'd that kid get so strong? I ain't gonna let you see me die. I won't give you the satisfaction of victory." His voice begins to rasp, and he remembers the first time he saw Shulk in Ose Tower before finishing with, "Looks like the student finally surpassed the teacher." He smiles slightly before slumping forward, dead.

Just before they enter the teleporter to leave, Fiora turns to Shulk and says quietly, "Shulk, his wounds..." Shulk does not answer, but begins to cry.

Trivia

 * He may have been intended to drop Dickson's Amulet, an unused item.
 * Dickson has hidden English voice clips in the game's files where he speaks to Mumkhar, Riki and Melia, as well as unused animations for jumping, possibly hinting he was going to be playable sometime in development.