Holly

Holly Murray-Lette (later changed to Holly Pele-Kann) is a bird that screams in a 360 area to destroy nearby glass. She helps in The Avian-Bovine War and The Bird-Loyalist War, although she also helped in smaller battles and misadventures. She appears in Angry Birds: Bubbles, the Special Edition, Angry Birds 3: The Final Flocktier, and Angry Birds: Out of Darkness. 

Appearance
Holly is an Ancient Murrelet with white top feathers and a dark gray underbelly. She has several feathers extending to the back, with feathers also sticking out of her head. She has a light gray beak and has blue eyes. In most versions, Holly has two good eyes, but in her modern appearance, she has one blind right eye. She also has two scars on that eye and the other eye, although only on the modern versions.

Not-so Peaceful All Terra Life
Holly was a Bird living peacefully on All Terra when the Pigs come and use the island to supply the Decipiger. They capture her and her friends and trap them in cages. Soon two other birds come in cages, one orange, and one green. They free themselves and beat the Pigs after freeing Holly and the rest of the flock. The orange one named Bubbles and the green one named Hal lead the flock through the island, disrupting the Pigs and even freeing one other Bird named Hallow. He ended up joining the group. Soon they raid a Pig castle and meet the Dark Knight and Ultimate Turkey. They don't join them on their quest, but they help repel the Pigs from the island. Soon after raiding the last castle, plans to blow up Bird Island are found. Holly and the others immediately board a shuttle and get on the ship, the Decipiger. They fight the way through and eventually cause the battle station to self destruct and celebrate on Al Terra below. Holly is soon able to gain enough courage to confess her love to Callahan, and they begin their relationship.

Beginnings of a New Order
Soon after, the Former Order call King Cumulus to break out of prison when he realized that the door was weak due to Bubbles' Flock's bombings. He breaks out and makes a deal with the Pigs. He and his Kingdom would help them get the eggs. They agree, and King Cumulus steals the eggs and leads the advance for the Diamond Turtle as well. Holly and Callahan rally the others to go help Red, and they go and attack his fortresses. They are defeated and pushed into Dreamland. Here Holly has a dream of Callahan's death, but she can break through and find the others, and they push back King Cumulus's forces but are unable to get the eggs back, and King Cumulus steals the Diamond Turtle.

The New Order
Holly and the others are pushed to the brink at the Battle for the Last Hope. The Cows bring out the Diamond Turtle and destroy the Birds causing many Birds, including Callahan, deaths. Holly couldn't take it anymore and almost goes insane in the mountain caves until something draws her to a Mansion built over Callahan's house. In there, she discovers Callahan's ghost, and she vows to revive him. She joins Red and his rebellion and decides to take Callahan's revenge.

Resurrection
Through currently unknown means, Callahan and many of the killed Birds are resurrected. Callahan and Holly meet up again in person and marry each other. As shown in The Adventures of Holly and Callahan, they have several adventures before they finally settle down in a small village on Piggy Island and have a son, Henry.

Insurrection
Suddenly Callahan disappears, and Holly follows after, leaving Henry with Hank's family. Years later, Malice manipulates Henry into believing that his father was talking to him through the spirit realm. He is told that evil is gathering its forces on a remote island and that they must stop it. They must find a Wayfinder to locate them. They are given a guide, Dave to go find it. Holly reappears when she appears behind Sarah and her flock and when asked why she was there, she said she was compelled to. She had seemed to have lost her memory and didn't even know of Callahan's disappearance. After a quick reunion, Holly joins the flock on the final mission to destroy evil once and for all.

Destruction
Holly is present when it is revealed that Dave is Malice himself, and they are captured. She sees the destruction of Piggy Island and realizes that this is it. If they fail here, then the world, perhaps the universe was doomed. They mourn the supposed deaths of Piggy Island's residence and can get loose thanks to Sarah melting the chains. They meet Reece, Red, and their flocks outside and decide to take two shuttles to board a ship they knew Malice was on. They board, and Malice greets them. He opens up portals worldwide and begins amassing an army of evil from universes, not their own. Holly is stunned at this; she hadn't seen anything like this since Callahan's first death. They can take down the ship by taking out the engines.

(To be continued)

The Decipiger Scare
Holly, or the Scaredy-cat as her friends call her during the events of Angry Birds: Bubbles, was a terrified bird. She never liked confrontation with the Pigs, making her not appear much in the earlier levels. Through the game, she learns to be braver. At the end of the game, she confesses her love for Callahan, the bird she secretly loved but never had the courage to say it...

The Aftermath of the Avian-Bovine War
Holly is much braver than during the Decipiger Scare. She fights against the Pigs with her lover Callahan until his death by the Cows during the Battle for the Last Hope. After Callahan's death, the Birds are forced into a retreat, and Holly is devastated and hides in the mountains near Callahan's house. She becomes depressed due to Callahan's death and vows to find a way to resurrect him. She retreats to the Mansion, which was built over Callahan's house, until Red finds her seeming crazy, but actually found Callahan's ghost. She vows to resurrect him, no matter what.

The Bovine Rebellion
Red had organized a rebellion against the Cows, and Holly gladly joined his cause. Although Callahan was still with her, she wanted revenge for his death. Later, the Blues revived Callahan, and she befriended them because of it.

Pre-Bird-Loyalist War
Holly lived peacefully with her husband Callahan until Callahan went missing. She didn't wish to lose Callahan again, so she sent out search parties, which found nothing. This depressed her even more than last time as she didn't want to lose him again. Soon after, she goes missing and leaves Henry, their son, to stay at his friend's house as he had nowhere else to go.

The Bird-Loyalist War
Holly reappears as her old self again, to her son as they were going on an adventure to stop evil. They ask where she was the whole time, but she doesn't remember. She didn't realize that Callahan was gone. She agrees to go along with them to avenge Callahan.

Vocal Abilities
Holly has been seen to be able to scream so loud that glass breaks around her. This is her main ability through most games. Holly in Angry Birds Ultimate has the Peace class.

Physical Abilities
Holly can fend off Cows and Pigs, as shown in Angry Birds 3: The Final Flocktier.

Callahan
She adores Callahan and fell in love with him. Callahan was her best friend and crush. Holly is able to tell Callahan how she feels about him after the destruction of the Decipiger, and he returned the feelings. They loved each other; they fought by each other and helped each other. Soon after, Callahan died when Cows overran their position, which caused the Birds to retreat to the mountains, where she hid for what seemed like years until being discovered in a mansion by Red. She had found Callahan's spirit and was talking to him. She vowed to bring him back to life. Later, when Callahan had been brought back, she married him and had a son, Henry.

Gummi
Holly never liked Gummi as she thought he was too immature, although she came to enjoy his company at times.

Logan
Although she was a bit scared of him due to his way of popping enemies, Logan was a good friend, although, without him, Holly confesses that she would have been dead multiple times.

Bubbles
Holly and Bubbles always respected each other. They protected each other and grew to have each other's backs. Although Bubbles can be a bit too immature at times.

Hal
At first, Holly and Hal didn't get along, but after Holly grew a spine, they became good friends. Hal is seen occasionally talking with Holly, Callahan, and Logan.

Hallow
Hallow is a strange bird. Holly realizes this and keeps her distance, although Callahan seems to have no problem with him.

Trivia

 * Her name comes from SweetSquidtea's first bird, based off on a purple bird in an old video. Other than the name, she shares no other similarities.
 * Her appearance in Angry Birds: Out of Darkness is based on Herobrine's design in Fallen Kingdom.