Anthiese has light yellow underbelly scales, crimson horns and inner-wings, and a mostly red body, similar to her mother, Liprica's, appearance. She has a RainWing head, limbs, and wings with a LeafWing tail, neck, and spikes.
Note: Spoilers for Fire Emblem Echoes: Shadows of Valentia up ahead, but I made them into a WoF-version. Please read at your own risk if you don't want FE Echoes spoilers!
In 5,008 AS, Anthiese was born as Princess Anthiese of the RainWings to King Lima IV and Queen Liprica, who died when she was less than a year old. Anthiese bore a striking similar resemblance to her mother. This RainWing lineage, though, was very different to the current RainWing lineage in canon. She bore a mark on her paw to say she was part of the royal bloodline, which would tie her to a similar individual she would fall in love with later on.
She became close to Conrad, one of her half siblings and one of Lima IV's many dragonets when she was young.
Three years (in dragon years; 10 years in human years) prior to The Missing Heir, which Anthiese is the protagonist in, the RainWing royal palace was bombed by SkyWings' dragonflame cactus by a SkyWing general named Desaix, who hoped to instigate a coup against Lima IV. Mycen, Alm's grandfather, rescued her, although he could not find Conrad when Anthiese asked for Mycen to rescue him. They had to flee away from the royal palace outside of the Rainforest Kingdom, causing most of the Rainforest Kingdom to believe that nobody, even Anthiese, survived. Mycen then brought Anthiese to Ram Village, a small village in the Mud Kingdom, where she would hopefully forever be safe, and gave her a new name, Celica, that she would have for many years and be known by.
In The Missing Heir, during the time she lived with Mycen, she became close to Alm, Mycen's grandson who was half LeafWing and half SkyWing. They were inseparable. The two loved to compare the two marks on their hands. However, Slayde, one of Desaix's cronies, came to Ram Village. After he was repelled, Mycen thought that Celica would not be safe now that they knew where she was, alive. She was brought to priory in a SeaWing village, Novis, where she was raised by Nomah.
One day, Celica had a dream of Alm's death and believed that Mila, the one who controlled the crops, was responsible for the crops not growing. Celica then left and voyaged across Pyrrhia and met mercenaries that helped her on the way.
After a bit, she adventures back to the Rainforest Kingdom, where she finds Alm, although not knowing her true heritage. Overjoyed she found Alm again, they soon got into an argument about Rudolf, the ruler of the SkyWings at the time. Celica said that Rudolf wasn't as evil as everyone said he was. However, Alm said that he invaded the Rainforest Kingdom already and he remains to keep assaulting the Rainforest Kingdom. He points out that the late king is responsible for provoking the kingdom. Celica accuses him of vying the SkyWing throne. Alm feels insulted and says he only wishes to protect the RainWings and their kingdom, not to attack them, and if the missing princess of the RainWings took the throne (unbeknownst to Anthiese that it was her), he would return to Ram Village alongside her. Anthiese, not remembering her past, denies that the missing RainWing princess is still alive, frustrated. She leaves and continues her journey to find Mila.
Immediately after leaving, Celica is ambushed by mysterious dragons claiming to be followers of Mila's evil elder brother, Duma. A mysterious masked dragon knight appears before them just before the mysterious dragons attempt to kidnap Celica. The masked dragon repels away the so-to-be kidnappers, where Celica thanks him and asks for his assistance and name. The masked dragon says he cannot assist and give her his name as he flies off. Upon nearing the RainWing royal palace, she encounters him again, where he says he wants to take her to a certain place of the Rainforest Kingdom near the Mud Kingdom.
On the way, the masked dragon warns her to take a safer way. Celica does not take the safest way and gets caught in a landslide, but is saved due to the masked dragon's intervention. However, the landslide prevented her from being reunited with Alm, cutting off their time together.
They begin their journey north again, where they meet Palla with her sister Catria as they are caught in a battle to help save their sister, Est from Grieth, a SeaWing pirate who has been pillaging SeaWing villages for years. Celica and her friends defeat Grieth once and for all as they recruit Atlas, a villager who lost his relatives to Grieth, Jesse, a mercenary who attempted to rescue Est when she was being attacked by Grieth, and Sonya and Deen, Grieth's former henchmen.
At Grieth's fort, they find a female LeafWing named Irma captive. Irma then recognizes Celica as Princess Anthiese of the RainWings, since she bears a striking resemblance to her mother, Liprica. Pledged by Celica, now Anthiese, Irma explains about Liprica's past: Liprica was one of the many wives of King Lima IV of the RainWings who was forced into her marriage with him, who later suffered from illness and died when Anthiese was a little older than newly hatched. Anthiese feels sad about it, where Irma gives Anthiese a circlet that belonged to her mother that shown she was part of the royalty of the RainWings.
Anthiese then arrives at Mila's home, where she finds out that Mila's home is under control of Mikhail, one of Duma's followers who she and her forces defeat. Anthiese then enters Mila's home and finds Mila absent. Mila's followers then say that Rigel attacked and sealed away Mila. Anthiese then accepts her role as the princess of the RainWings and accepts her royal circlet truly.
After her coronation, Anthiese then enters the eastern gate and heads to the Sky Kingdom to press her investigation.
She then learns that Mila is being held captive at Duma Tower by the masked knight, whom they set off to unseal Mila from being captive. She is confronted by numerous Duma followers on the way as she gets injured along with her friends.
A little while later, the masked knight dragon reveals himself as one of Anthiese's half siblings, her half-brother Conrad. Conrad joins them and Anthiese is overyjoyed to be reunited with her brother.
Conrad then leads Anthiese and her forces to Sage Hamlet where animus dragons practice and cast spells. There, they speak to Halcyon, a NightWing former follower of Duma and an animus dragon as well as Conrad's master. Halcyon casts a spell on Alm so Alm can truly have some more power, where Halcyon also allows Anthiese to send Alm an Astral projection of herself to reveal to be the long lost princess of the RainWings, Princess Anthiese.
Then, a black RainWing Anthiese remembered from her childhood appeared with a dagger. It turned out to be Ex-Queen Amazon, one of the many wives of King Lima IV who wanted to kill her since she believed no part of royalty could be from a different tribe other than their own and no hybrids. She then attacked Anthiese's party, where they all fought off fiercely and defeat her. Amazon says she's sorry as she allows them to carry on and she learns her lesson.
Anthiese and her party then ascend the tower, where Jedah awaits to tell them Mila's current fate. In the basement of Duma's tower, Mila is dying. Alm was currently being attacked by zombie NightWings, where Anthiese pays her concern and allows herself to get captured to spare Alm, her party, and Jedah. Jedah agrees not to kill any group and warps Anthiese, himself, and her party outside with his animus magic. After they all witness Alm kill King Rudolf of the SkyWings, it turns out that Rudolf was Alm's father. Anthiese then tells Jedah that she will offer her soul to Duma on the condition that Jedah will not harm him and to help revive Mila (even though she was animus enchanted by Duma before they warred) for the sake of Pyrrhia and Pantala.
After Alm arrives in Duma Tower, he finds Anthiese in a cell, and when he tells her that he is going to kill Duma as requested by Rudolf, Anthiese tries to convince Alm to not, fearing that Pyrrhia and Pantala will become more barren than it already is without Duma. Jedah allows Anthiese to give a final goodbye to Alm as she and Alm say goodbye, where Anthiese tells Alm that her only wish is for everyone, including Alm, to not be killed or hurt and that she wished that things would've been played out differently as she wishes that she still stayed in Ram Village the way life used to be.
Alm then goes farther into Duma Tower as Jedah says that he never had the power to revive Mila when her enchantment wouldn't work, claiming it was beyond his ability. She is then shocked about Jedah's lie, to which he tells Anthiese to blame Mila for her displeasure and abandoning Pyrrhia and Pantala. He then obliterates Mila, killing her. Jedah then proceeds to sacrifice Anthiese to Duma by having the latter steal her soul to make her into Duma's puppet. Jedah then teleports Anthiese to the treasure vault, where they await to fight to the death.
When Alm arrives, he and the possessed version of Anthiese clash once and for all. During the fight, Anthiese asks Alm to kill her before she can kill him, which Alm is reluctant to do so. As they fight, Mila's voice instructs Alm to grab a legendary sword to fight, which he does, and they clash with Alm having the advantage, supposedly killing Anthiese. Some blood drips from Anthiese's body as Alm mourns over her carcass.
However, magic suddenly lift's Anthiese's body into the air and removes the sword stabbed in her chest to revive her. Alm questions how she's alive, but Anthiese says she doesn't know how and apologizes for arguing with him earlier, causing the two to come together to stop Duma.
Using Mila's Turnwheels to open the gate to Duma's domain, they kill Jedah and his two daughters, Hestia and Marla in the process to allow them to face Duma. Duma is slain due to their power, but Duma revives himself and Mila with his animus powers. Duma said his powers went out of control for thousands of years and he wasn't able to control it, and he thanks the two for helping him go back to normal as he and Mila go back to slumber as Duma entrusts the future to the "weaker dragons", knowing the results of Duma and Mila's beliefs would serve as lessons about the extremes that can occur when vying for pleasure and strength.
Back in the Rainforest Kingdom, the RainWings and the SkyWings become friends yet again, where Anthiese and Alm shortly fall in love with each other and know that they'll officially marry when they get out of dragonethood, and during the time they restored peace to wars caused all over Pyrrhia and Pantala, with even some saying that Anthiese was like the reincarnation of Mila herself through the efforts that Anthiese made towards the world.