Appearance
Geyser, Caleb Z. Martin, dons his iconic blue and black sci-fi armor suit. He prefers his face to be seen at all times as he cares less about hiding his true identity than the other heroes of the Elect Few. Caleb himself has dark-blue eyes, long spikey jet-black hair that's pointed to the front but slightly off to the side. He stands at about 6', 1" and weighs in at 205lbs with very fair complexion. Little about his appearance changes from book to book except that the blue in his armor gets darker and darker. At times, he's seen wearing a tattered coat over the armor or some piece of clothing over the armor. By Book 4/5, his armor gets restored to its colorful glory and augmented.
History
Caleb Martin is Jake’s best friend. He's the big brother of the team and an incredibly skilled fighter, marksman, swordsman, and acrobat, but also the oldest of the gang. At times, he acts smarter than the others, but Derek's the one with the slightly higher IQ. Sometimes, he and Derek compete in brain games to see who's the smartest from time to time. He's also cranky a lot of the time, but the gang has gotten used to his mood swings. At one point, the “invincible trio” (Jacob, Derek, and Victor) tried to take Caleb on in a duel while Caleb was blindfolded and weaponless. The ultimate showdown was not only a spectacle but an embarrassing one for the "invincible" trio, forcing them to ditch their name within moments. [1]
Caleb lives far out in Arcadia, which is great on Independence Days as they have the best fireworks, plus Jake and the gang always played Halo, Call of Duty, and Gears of War at Caleb's house on the weekends, but Caleb has been away for the past few weeks...
Gaining His Hydrokinesis

Orbs, usually stored in the chest for the user's access to power upgrades
Like Jacob, Caleb was also born with his water manipulation ability, but it took his meeting with the Select Few to finally unlock his Hydrokinesis.
ICE BLADES: Geyser's go-to move is letting the condensation drip from his arms, coating his hands, and then he freezes the coating into long ice-blades. He can chop through obstacles with speed and slice through foes with ease.
GEYSERS: Hence the name. Water geysers serve as both Geyser's fallback attack when overwhelmed and conversely his preferred surprise attack to begin his onslaught. Unlike natural geysers, which are always hot, Geyser can make his geysers ice-cold or molten-hot with a simple thought.
COATED WEAPONRY: Geyser loves his use of water almost as much as his love of sword-wielding. To bridge the gap, he tends to coat all his weapons in razor-sharp ice, both offering twice the cutting power of his normal weapons and staving off wear and tear on his prized possessions.
INVISIBILITY: Going from seen to unseen is as easy for Geyser as boiling water into steam. In his steam form, he's virtually invisible, appearing as nothing more than an unsuspecting fog, drifting in the wind.
Power Level
At the start of his journey, Geyser is already far ahead of Jacob and the team in terms of combative ability. His menacing size combined with his two-year seniority over everyone else puts him at Superior Superhuman at the start of Book 1. Due to events that arise by the end of Book 1, he becomes the reason for Jake's "villain phase", where Geyser remains at his current status until Books 4/5 where he finally break into Legendary Superhuman.
Forms
Geyser has three Forms of power. Armageddon is unlocked fairly quickly as Geyser tends to lean into the Dark more than others at his age, and Armageddon is his Dark Form. Poseidon, his Light Form, on the other hand is rarely seen in use.
Villains

Cytro, age 17
Over the course of a decade, Geyser fights a very different slate of villains from Jacob although in Book 1, he does face many of the same notorious villains Jacob and the team do. In book 1, their greatest foe is the recurring Kyle Delcomish of the G.U.N.S. (Gang Under Nomadic Savagery) who are super-powered thugs, able to manipulate fire, shadow, and poison. They seek the one that "put them in prison". They seek the one "who shrouds his face in shadow". Anyone in the way of their target gets eliminated, and Some City failed to defend them civilly so they prey upon its citizens as "justice" for taking away their livelihood.
In book 2, Geyser is the old friend turned evil with the power of Hydrokinesis and an entire underground network of villains at his disposal. By Book 4, Geyser returns to the Light a redeemed hero full stop to assist Jacob on his journey.
Other Media
Cytro-Verse https://www.cytroverse.com/
"Supreme Heroes", Book 1 - https://www.iuniverse.com/en/bookstore/bookdetails/160300-Supreme-Heroes
"Supreme Heroes", Video Game - https://store.steampowered.com/app/3431600/Supreme_Heroes/
"Cytro: Dirge of Indemnity", Book 2 - https://www.iuniverse.com/en/bookstore/bookdetails/190878-Cytro-Dirge-Of-Indemnity
- ↑ Supreme Heroes, published 2009, iUniverse

Video Game box art