Angel

Angel, known to the Vault Hunters as the Guardian Angel, is a Siren with the powers of an A.I. (Artificial Intelligence) and guides the Vault hunters. She is a woman with pale skin, black hair and piercing blue eyes.

Background
Angel is the daughter of Hyperion programmer Handsome Jack, then known as John. Her mother left them for unknown reasons related to Angel's Siren powers (or possibly, was killed by them). Jack tethered his daughter to an interface, granting her control over most technology. He then orchestrated the events of the first game through his daughter.

Borderlands
Angel watches over the Vault hunters via the ECHOnet, due to her artificial intelligence-like abilities. This connection is later revealed to be Angel's 'eyes and ears' monitoring the movements of the Vault hunters when the ECHOnet is shut down, and her messages at this point indicate her loss of awareness about the course of events.

The final cinematic reveals that Angel is operating from, or through, a Hyperion Satellite in orbit around Pandora, foreshadowing her involvement with Hyperion.

While her ulterior motivations are unclear, Angel is primarily interested in the Vault hunters obtaining all of the fragments of the Vault key and being present at the Vault when it is eventually unsealed. Later in the story, it becomes clear that she wished to prevent The Destroyer, imprisoned within, from escaping the confinement of the Vault. This goal is ultimately carried out by Angel's, and by proxy Hyperion's deceit, something she expresses regret about having to do, but insists that it was the only way to ensure that events unfolded appropriately. This turns out to be a lie as well, as the ultimate goal for the Vault's opening was the supply of Eridium that Handsome Jack wished to exploit for his own gain.

Borderlands 2
With a steady supply of Eridium and the Vault key stolen from Patricia Tannis, her father used her as a catalyst to charge it, so he can awaken the Warrior. However, this leaves Angel dependent on a constant supply of the element, as disconnecting her from that supply will kill her.



She assists the new Vault Hunters in stopping Handsome Jack, similarly to the first game. It is also revealed that Angel betrayed the first Vault Hunters at some point, nearly resulting in their deaths during an attack on New Haven. She betrays the new Vault Hunters as well, deactivating Sanctuary's shields, and rendering the city vulnerable to Hyperion mortar strikes, which almost demolishes Sanctuary. After said events, however, she expresses regret for doing so, and turns on Handsome Jack, and continues to assist the Vault Hunters.

She later reveals that the Vault Key is with her, but there are three obstacles between her and the Vault Hunters. The first is a 'Death Wall' that only Hyperion personnel can pass, the second is a heavily armed bunker, and a door that only Handsome Jack himself may open. She suggests going to Opportunity, a massive city Jack is building, to kill one of Jack's body doubles to obtain a biosignature, as well as a voice modulator. Jack discovers her deceit, and tells her to 'say goodbye'. She replies with 'See you soon'. Roland suggests going to Thousand Cuts, and recruiting the help of the Slabs and Slab King, who turns out to be Brick. The Slabs then provide air support in assaulting the Hyperion compound where Angel is.

Once the Vault Hunters passes the three obstacles, she reveals her true form as a Siren, and her involvement in Jack's plan. She asks the Vault Hunters to destroy the Eridium Injectors, which make her more powerful, thus being able to charge the Vault key. However, destroying the Injectors would result in Angel's death. She accepts this, saying it's 'ending a life of servitude'. Once the final injector is destroyed, Angel falls to the ground. Jack pleads with her, saying 'it's not too late to make things right.' Angel, with her dying breath, calls her father an asshole.

Quotes

 * "Don't be alarmed. I need you to stay calm and don't let on that anyone is talking to you. Start making your way off the bus. You don't have any reason to trust me, but I need you to believe that I'm here to guide you - I'm here to help you find the Vault. In a moment, you'll be greeted by a funny little robot. Do everything he says. You'll know what I mean when it happens. I'll contact you again soon." - Upon arriving in Fyrestone.
 * "Excellent! I knew you were the right choice, friend. Now, go. I'll contact you again soon." - Upon defeating the bandits in Fyrestone.
 * "You did it! I knew you were the right choice. Oh...! That poor little robot needs our help. Would you kindly give him a hand?" - Before receiving Claptrap Rescue
 * "That little robot is hurt. He isn't going to last very long without attention. Why don't you look around for something to fix him up?"
 * "He seems to be okay. Now is the time to get moving and play your part in the journey to come."
 * "People don't yet trust you. If you're going to ever find the Vault, you'll need the aid of the people. Helping Doctor Zed with his Nine-Toes problem is a good move."
 * "You are about to face your first real challenge. I hope you've toughened up enough."
 * "That was the first step on your journey. You must listen; who I am is not important. The first thing you must know - the Vault is real. People will mislead you, they will try to use you, and you cannot be swayed in your purpose. The Vault is here, and we will find it. This world is full of dangers. Steel yourself and go. I'll be watching."
 * "This man, Sledge, has something we need. You are going to get it from him. Sledge is a bad man who has done terrible things to the people of Fyrestone. Do what you must."
 * "You should be able to get into the mine now. There is nothing between you and Sledge, and we're be (sic) one step closer to the Vault. I believe in you."
 * "Everything you've faced up until now has been simple. You are about to face a real challenge in Sledge. Do not underestimate him."
 * "This one is a brute, and he has a powerful shield you will need to whittle down before you can hurt him. Don't let him touch you."
 * "I bet you would like to know what that is. The Vault is real. What you are holding is the key that opens it... one part of it, anyway."
 * "You found another piece of the key without my help. Or did you? I'm always watching you, friend. Be careful. Others are starting to see their own opportunity."
 * "Prepare yourself. Your next challenge awaits. It might seem insurmountable, but you can do this, you will prevail." - Before facing the Rakk Hive
 * "The Crimson Lance are about to make an unpleasant discovery and learn a harsh lesson... Oh no... No, no... No! This wasn't supposed to happen! Stand by." - After Commandant Steele reveals that there is no 4th Key fragment after you kill Baron Flynt
 * "This is not how it happens. Can you see me? With the ECHO network down, I can't see you, we're flying blind, friend. Our window is closing. The Vault can only be opened every 200 years. If it isn't opened soon, your chance will be lost..."
 * "This is it! The reason you're here. I've guided you to this point, and you've done so well. Know that you are ready for this. When the Vault opens, brace yourself. I believe you can do this." - Before reaching the Vault in Eridian Promontory
 * "Don't give up! This creature may be immortal in its own realm, but in this reality it cannot survive without a host, and that makes it vulnerable. When it becomes flesh and blood, it can be hurt, even killed. You just need to know where to aim." - after Steele is killed
 * "Do you feel that I betrayed you? Do not. I am possessed of a sight that allows me to look forward and backward along the timeline, and the release of this creature was inevitable. There was only one chance for this dimension's continued existence. A hero. Someone who was at the right place, at the right time, and strong enough to push back. I have given you the unique opportunity to defend the existence of all that you know. Go! Fight! Be that hero. I will help you however I can." - from the mission description of Destroy The Destroyer
 * "You opened the Vault. I'm sorry I couldn't warn you about what was in it, but for you to be there to stop it, it couldn't have unfolded any other way. You did well, and your actions haven't gone unrewarded. The Key won't open the Vault for another 200 years, but I'm sure Tannis will pay you quite the fortune for it! Now, go. I'll be watching."
 * "Dad... I have to tell you something. You're an asshole." - In her final moments

Trivia

 * Angel is watching over the Vault hunters by way of an orbiting Hyperion satellite. The name "Hyperion" means "Watcher from Above".
 * The Claptrap Angel asks the Vault hunters to repair in Fyrestone will eventually change into the Interplanetary Ninja Assassin Claptrap.
 * Angel appears in the Borderlands 2 artbook as "Angel". The page includes mostly concept art and what appears to be an in game model. The concept art shows her having tattoos like a Siren.
 * At the beginning of Borderlands 2, while Angel is hacking a door she says "executing phaseshift." Since Siren abilities are known as "Phase-" (Lilith's Phasewalk and Maya's Phaselock) and Angel being hooked to an artificial intelligence, this may be the title of her Siren power.
 * In the concept art book that came with the Collector's Edition of Borderlands 2, it is stated that Brittani Johnson was cast as the Guardian Angel before the character was designed, which lead the designers to base the CG version off her real appearance.