Xander Griffin

Xander Griffin is the CEO of Tression and a Yellow Lantern, he mainly fights Tai Pham though he does want Tai to join him.

Pre-Yellow Lantern
Xander didn't get along with his family for a lot of reasons which meant after he left for college he didn't talk to them again besides for weddings and funerals.

Xander left college a hopeful young man but without much of clue what to do with himself as he had skills but no clue on what he could do with said skills. A friend of his told him about a meditation group that Kim Tran ran, He and Kim got along as both of them wanted the world to be a better place. He ended up finding out she was a Green Lantern, he kept her secret, along with other ones as he was someone she trusted with info along with helping her from time to time by looking into things for her, over time Xander wanted a ring of his own but no ring came and Kim told him she wouldn't get one for him, Xander had a fight with her about it and then left to make his own path.

Yellow Lantern
While on earth dealing with Hal Jorden, Sinestro looked around Coast City to see if he could make an ally/spy to keep an eye on the city/earth when he was unable to, Sinestro found Xander who was still upset over not having the power he wanted, Sinestro gave Xander a Yellow Lantern Ring, and told him about the things Kim didn't know about when it came to the Lantern Corps along with telling him to stay on earth.

After gaining this power Xander was finally able to decide how he'd make the world a better and safer place, he'd first need money. He was always good with tech and programing so it being a tech start up just felt right, and due his clever designs along with the fact that other tech companies suddenly had whistleblowers who were before too scared of said companies to come forward, came forward which started scandals for the companies. Xander named his new company after the man he thanked for his power though he made sure it was hard to tell, anyway the company was named: Tression.

New Green Lantern
Xander was just living his normal life when he heard that Kim Tran had died which made him think of how he thought he could make China Town a better place since it was somewhere that Kim cared about plus he did plan on making the whole city safe so it wasn't a bad place to start. He decided to go to the funeral as he wanted to pay his respects along with meet her family, while he was there though he noticed that Kim's grandson had her Green Lantern Ring, after seeing that he decided he wanted to know more about the kid since it was likely that the kid would become powerful along with that fact that the kid might be like himself, he gave Tai his business card.

Soon after Xander got contacted by Serena who set up a meeting for Tai as for a school project about innovation, When the kids (Tai, Serena & Tommy) where within his office in Tression Tower he told them about his thoughts on innovation along with legacy, how he felt holding onto the past was what keeps the world imperfect. He also told them about his plans for China Town, making it into the Gold Coast.

He started looking more into Tai along with the Jade Market as he was planing on buying it, while out one night he ran into Tai while he was acting as a Green Lantern, at this point he told Tai that he knew he was a Green Lantern due a facial recognition software his company is working on (which while a lie about how he knew is a real thing his company is working on), along with the fact that he had known Kim well and knew she had been a Green Lantern.

A few days later Xander was doing some recon for Gold Coast along tracking down the kids who had been trying to scare Tai's family away, he ran into Tai (whom he was already thinking of checking in on) who had been having a fight with his friends, said friend came down and due to Serena's scrabble skills was able to figure out Tression was a anagram of Sinestro, after which Xander did tell Tai he was a Yellow Lantern, he gave a spare Yellow Lantern Ring (which Sinestro gave him in case he found a good ally) to Tai along with showing the kids who had been scaring his family tied up to Tai, the idea being that Tai could some justice the Xander way but Tai said no and fought Xander.

A Mentor
John Stewart was sent to find the new Green Lantern, Tai, the Green Lantern Ring ghost of Kim & Xander all didn't want that to happen. after Tai and his friends talked about what to do they ended up going to Xander and told him what was going on, at which point Xander could guess it more then likely one of two things could happen: 1. Tai loses the ring but tells John Stewart about him or 2. John Stewart starts training Tai which mean it'd be harder dealing with Tai.

Xander started trying play on Tai's fear of losing the ring to make sure he didn't go to John, while doing that he and Tai also treid to come up with a few plans on how make sure Tai wasn't found, said plans included: being at a art camp, faking Tai's death, making John find a fake ring. While the two tried to come up with ideas Serena contacted John believing it was likely that since Xander stood to gain from Tai losing the ring it was likely that John wasn't going to take the ring, she told him that it was likely that if Tai wasn't home he'd be with Xander Griffin.

John showed up at Tression Tower Xander did try to keep everything under control but all it took was a phone call with Serena for Tai to leave to go talk with John and start getting trained by both him and some of the other Green Lanterns of earth.

A week later Alexandra Dewitt (A newer Yellow Lantern) came by to give Xander some news from space, mainly about the fact that Darkseid is coming to Earth, Kyle Rayner and Tai were there when Xander was told, they left afterwards.

Powers

 * Yellow Energy Conduit: The rings use yellow energy, supplied by a Power Battery, which in most cases takes the form of yellow light. Yellow Power rings, considered by some to be one of the most powerful weapons in the known universe, has the ability to affect and use fundamental forces of the known universe, including electromagnetic energies such as gravity, radiation, heat, light, and powerful blasts of concussive force. It is also theorized that the ring also has a basis in other dimensional energies commonly called magic by users of such energies. The ring can also create fields of force formed from an unknown energy that was bound by the users' will. The limitations of such use are the skill, knowledge and imagination of the user.
 * Energy Blasts: The ring can be used to fire blasts of yellow energy or create weapons such as projectiles of them. The ring can project beams of force powered by the will of the user. The weapons power is more an indication of the will of the user.
 * Force Field Generation: The ring can create various force fields of various sizes and shapes to protect the wearer and others around him. With the cosmic scope of a Sinestro corpsman's duties, it is only natural that the power ring is designed for operation in space. The ring creates a force-field around the wearer, protecting him/her/it from the hazards of the void including filtration of stellar radiation and microscopic particulate matter which would ordinarily be fatal should the space debris strike the ring wielder at high speeds. An atmosphere appropriate to the ring wielder's biology is created inside the force-field, body temperature is maintained and waste products are removed. Gravitational stresses which could cause injury are stabilized for the ring wielder. Theoretically, a ring wielder could use the ring as his/her/its sole source of life support. The force-field seems to be created instantaneously, whether this is due to programming or an instinctive reaction from intensive training has not been established. It could be considered as a subroutine of the ring's automatic defensive system, but as of yet, this theory has not been proven.
 * Energy Constructs: The ring can form constructs of yellow energy. The primary function of the Power Ring is to provide a weapon capable of transforming the wearer's thoughts into physical constructs through the wearer's mastery of Fear. A Sinestro Corpsman can create any particular items or construct that they can imagine as long as they have the mastery of fear necessary to will it into existence. The constructs are made out of yellow energy, which is a tangible form of pure fear, and they exist only as long as a Sinesteo Corpsman is fueling it with their mastery of fear. Items created by the rings are not indestructible and are only as powerful as the inspired fear of the Sinestro Corpsman creating them. The types of constructs usually reflects the ring wearer's personality.
 * Instill Fear: the Power Ring is unique in that its base of power, fear, can be manipulated by the ring user. An opponent's fears can be laid bare by delving into their minds. The power only works on the direct emotion of fear. This allows them to create the energy constructs of an opponent's worst nightmare. Also, once that fear is exposed, the ring's ability allows the wielder to amplify the fear to the point of irrationality and true horror on the part of victim and conversely empowering the ring wielder.
 * Phasing: The Power Ring allows the wearer to pass through certain solid objects, such as walls. Which objects that are not penetrable are not known, but it may depend upon the strength of the wearer's mastery of fear and the density of the object's molecular structure.
 * Kryptonian Charging: Similar to how the light of a Green Power Ring can be used to create artificial Kryptonite energy to harm a Kryptonian, the yellow energy from a Yellow Power Ring can charge the powers of a Kryptonian or Daxamite.
 * Environmental Playback: Upon request, the power ring can recreate a holographic environment based on data in its memory banks. The ring wielder can observe events in a ghost like state, but the ring wielder cannot alter the outcome of the playback. All objects in the playback will appear in the full spectrum of colors, regardless of the wielder's level of expertise creating simulacrum's. The power ring will automatically end the playback if outside interference warrants the ring wielder's undivided attention.
 * Energy Twin: The power ring allows the wearer to create an "energy twin" of his/her/itself that can travel at far greater speeds than that of the ring wielder's physical form. While the energy twin is active the ring wielder remains motionless, his/her/its life force is needed to guide the energy twin. The energy twin can not alter its surroundings, and may only be perceived by another ring wielder as a yellow, ghost like image. Any knowledge gained by the energy twin is transferred back to the ring wielder's physical form upon recontact with the body.
 * Energy Absorption: The ring can absorb and store most other energies. Unlike the Green Lantern power rings, a yellow power ring can replenish the normal store of energy the ring has. A ring that needs recharging, but contained a store of electricity could only discharge that electricity, for example.
 * Flight: By the manipulation of anti-gravitons and directed molecular movement, the ring allows the user to fly at incredible speeds. In atmosphere, a Sinestro Corpsmen has been known to fly as fast as Mach 10 in atmosphere by creating an aerodynamic envelope around his body. Towing others, usually within a bubble, his speed is limited to the twice the speed of sound or 1440 mph. In space, Sinestro Corpsman's speed can be significantly greater and has been known to approach 80% of lightspeed in normal space. Flight is possible at velocities exceeding light speed. In atmospheres, air friction is not a hindrance, since heat is either absorbed or reflected by the ring's field.
 * Wormholes & Spacial Warps: The power ring grants its wearer access to wormholes in space, enabling the ring wielder to rapidly cut time and distance needed for transport. Black holes can be navigated by experienced ring wielders.
 * Limited Cellular Regeneration: This ring has a limited ability to heal physical injuries and this seems to be a feature held over from the previous incarnations of the ring. Sinestro Corpsman can use the ring to repair minor injuries in himself or others.
 * Electromagnetic Scanning: The ring has a wide range of detection abilities based on the imagination of the user. If one can conceive of it, he can probably detect it. Magical effects like clairvoyance, seem to be beyond the scope of the ring. Most normal electromagnetic phenomena are within the range of the ring, including radio, television, infrared, ultraviolet, and high frequency band communications.
 * Universal Translator: Keeping in mind the myriad of worlds, life forms, and cultures throughout the cosmos, it is understandable why Sinestro added a translation system to the power ring. The power ring can translate virtually any language in the universe, facilitating diplomatic encounters rather than violent confrontations.
 * Material Alteration: The Sinestro Corpsman's uniform is not made out of fabric. It is created by the Power Ring whenever the wearer wills to wear it. It automatically appears over the wearer's normal clothing, and vanishes when the wearer wills to return to their civilian attire. Most Sinestro Corpsmen wear similar uniforms that are programmed into the ring by default. However, each Sinestro Corpsman is able to adjust their uniform to fit their own needs, personalities and whims. The yellow parts of the wearer's uniform are usually very warm or hot to those who touch it, while the black parts are very cold.
 * Ring Duplication: Most Power Rings are capable of automatically duplicating themselves. Each duplicate typically shares the qualities and capabilities of the original ring. While the thought of an unauthorized person getting a hold of a power ring and making duplicates for nefarious purposes, their ability to inflict damage is limited because each duplicate still requires to be recharged by a personal power battery.
 * Emergency Beacon: A Sinestro Corpsman in distress can use his/her/its power ring as an emergency beacon. The alert can be directed to a Sinestro Soldier's neighboring sector, or it can be a Corps-wide alert.
 * Homing Beacon: A homing beacon in the power ring can lead one Sinestro Corpsman to another. The power ring can be ordered to disguise itself to elude power ring wielding trackers. Most often ring wielders will allow the beacon to signal their location to others.
 * Mind Alteration: As the power ring relies on thought and will to operate, mind tampering is not impossible, the real difficulty lies in properly applying the power. There lies a risk of catastrophic damage to the mind should mistakes be made. A ring wielder can use the power ring to erase portions of an individual's memories. Sinestro Corpsmen have used mind techniques as part of training. New recruits may be subjected to mind scans by other Sinestro Corpsmen. They are taught to build mental defenses to protect themselves from psionic attack. The power ring can also be used to beam information from the ring wielder to another being. Sinestro Corpsmen have used this technique to share information regarding their enemies during combat situations.
 * Security Protocol: The rings can be programmed. They can be coded to the wearer so as to make them unusable if stolen.
 * Preset Conditions: Commands can be stored in the ring to be executed at a later date, even if the bearer is not wearing the ring.

Weaknesses

 * Recharge Protocol: Formerly, the rings needed to be charged after a period of 24 hours, regardless of how often it was used. Currently the rings retain a charge until they run out of power. This variability ensures that the wearer takes greater effort to keep it charged. Sinestro's ring was originally charged by attacking Green Lanterns, presumably to tap into the yellow light of fear provided by Parallax who was trapped in the Green Lantern's Central Battery for eons. With the construction of the Sinestro Corps' Central Power Battery, a Yellow Power Ring has the same power limitations as a Green Lantern Ring.
 * 'Hope Weakness: The transmission and power of one of Sinestro's rings can be greatly disrupted by the presence of a Blue Lantern Ring.

This list of powers along side weaknesses comes from the Green Lantern Wiki which can be found here

Abilities

 * Technology
 * Programing
 * Inventing
 * Business Management
 * Linguistics: Xander knows a few languages: English, Japanese,  Vietnamese and  Russian