Manga in which the female main character was a hero who died and reincarnated as a child

Question

Read this manga approximately a year ago on mangabat.

Characters:

• Main character female was a hero for the church, she was used by the church to do their bidding. She always used a helmet/full body armor. Her face was not seen before reincarnation.
• Cardinal/priest was keeping her in check, don't remember a thing about him. Manga might have only glossed him over at the time.
• Former female comrade the mc met her current adoptive parent (after reincarnation) before as a comrade in the battlefield(?), said former comrade was a child/teen when they met but she (mc) was an adult at the time.

Story:

The main character has been killed(?) by the church/cardinal and is reborn(?) as herself but younger? She is taken by her former comrade as a daughter. She has a special divine(?) sword that can be summoned.

She is educated in history and has a panic attack when the teacher said that hero was just a mouthpiece/chess piece of the church.

Later, she reveals her secret while sitting on the bed to her former comrade. Even later, she reveals it to everyone close enough to her by summoning the special sword in a hall for everyone to see.

Answer 1

This is Devoted to Diamond.

The great hero Devota worked tirelessly to save the world from evil, only to be betrayed and killed by the very man who raised her. Luckily, she's granted a new life as a young orphan named Diamond and, through a twist of fate, is taken in by an old comrade, now a powerful duchess. The whole family dotes on her like she's one of their own, and as it turns out, she actually might be... But with her murderer still at large and her revenge still unfinished, will Dia be able to open her heart to love?

In her first life, the protagonist, Devota, was an orphan who was placed in the care of a cardinal and trained to defeat monsters. As an adult, she wore a full suit of armour, including a masked helmet, and her true identity and sex were unknown to most.

After the defeating the Demon King, she was betrayed and killed by the cardinal, but most people weren't aware of that, knowing only that she mysteriously disappeared shortly after the Demon King's defeat.

She then wakes up as a seven-year-old orphan named Diamond (Dia for short), who looks much the same as Devota did when she was a child. Not long after, she meets Ria, a woman she knew as a comrade in her previous life. Ria is now a duchess, and Dia is subsequently adopted into her family.

Although the family takes good care of Dia, she keeps her previous life a secret from them for quite a while. She receives history lessons, and during one lesson, faints after hearing the teacher describe the warrior, Devota, as a "tool" used for world peace.

Dia eventually discovers that Ria has retained Devota's armour and sword as mementos, stored within glass cabinets in her mansion, and this leads her to think that Ria still has fond memories of Devota, and that it may now be time to tell her who she was in her previous life.

She does so while the two are conversing alone in her bedroom, and magically summons Devota's sword into her hands for the first time. Soon after, she summons the sword again in front of the rest of the family.

The manhwa is still ongoing and can be read at Tapas.