Tyrell

Tyrell (Terrell in the Japanese version) is a playable character in Golden Sun: Dark Dawn. He is the son of Garet and a Mars Adept himself. He was first revealed for the game alongside his fellow party members Karis and Matthew, at least in terms of gameplay footage from E3 2009.

As a playable character
It is evident from trailers that he is one of the main party members that appears in battles in Dark Dawn, and he uses a similar collection of Psynergy as Garet did in Golden Sun, indicating his element as a Mars Adept. The E3 2010 floor demo footage showing him in battle shows him launching a fiery Psynergy in battle that looks like a 3D rendition of the Fire Psynergy series, as well as a confirmed return appearance of the Heat Wave Psynergy, the Flare Psynergy series, and what has been renamed the Starburst Psynergy series (the old "Blast" series that led up to Nova). Whether he also has the Move Psynergy like his father did, in a similar case to Matthew and Isaac, remains to be seen.

Biography
Tyrell is considered the son of the previous games' Garet on the basis of very similar appearance and what is confirmed from press releases that 30 years had passed in between Golden Sun: The Lost Age and Golden Sun: Dark Dawn and that the main characters of the game are the children of the main characters from the previous games. What is interesting to note, though, is that while he has a similar build, hair style, and hair color to Garet, his light blue eye color is much different from Garet's auburn eye color. For whatever reason, Tyrell isn't present on screen along with Matthew and Karis in the scene E3 2010 trailer when a Psynergy Vortex appears near the town they are at.

2009 Poster controversy
A point of contention among the fanbase that surfaced shortly after the posting of Tyrell's official artwork pictured at the top is the apparent dissimilarities in design between him and what was initially thought to be Tyrell's first reveal in the E3 2009 promotional poster, pictured to the left. However, slight differences in both hair color and wardrobe - noteworthy because Matthew and Karis are consistent in all design aspects between their appearances in the 2009 poster and their 2010 artworks despite possible lighting issues in the images involved - lead to the contention that this is, in fact, an entirely separate character.

Casting doubt on the assumption that this is merely a redesign of Tyrell that transpired in between the game's showings at E3 2009 and E3 2010 is evidence that lies within material from both E3 conventions. Posted by IGN at the same time as the Tyrell artwork above in 2010 was, where Matthew and Karis are shown as two among a four member party along with a second blond individual and an axe-wielder with auburn hair. The darker-red-haired party member of interest here has both the noticeably darker hair and a different jacket - a leather jacket like in the profile to the left - than Tyrell, which is evident from other battle screenshots like where it is Tyrell by himself that accompanies Matthew and Karis, where he is clearly identifiable in-game by his brighter-red hair and a wardrobe that matches the top portrait. Furthermore, the limited battle footage shown at the floor demo from E3 2009 shows that the male Adept to the right of Matthew and Karis is clearly the same design as Tyrell's portrait above, having the same brighter-red hair style and set of clothes, different from the character in the 2009 poster.

Among those that contend that this darker-red-haired character in a leather jacket is a separate character from the brighter-red-haired Tyrell wearing a shirt with bright yellow elements, another point of speculative debate concerns who exactly this character is. Doubt is cast on the notion that this is Garet as a middle-aged adult by the character's still-young appearance and, failing that, by the fact that this character's eye color in the 2009 poster is still similar to the light blue eye color of Tyrell, rather than the brown eye color of Garet. Remaining hypotheses revolve around the possibility of Garet having fathered more than one child.