Ok, it took me a while, but she's ready:

[hider=Not all problem children fall from the sky, you know?][b]• Name:[/b] Mordred [i]"The Knight of Treachery"[/i]
[b]• Class:[/b] Saber
[hider=• Appearance:][center][img]https://i.imgur.com/wiEkkiAl.jpg[/img] [img]https://i.imgur.com/1z8uluvl.jpg[/img]
With and without her armor[/center][/hider] 
[b]• Personality:[/b] Mordred is a problem child, simply put, she seems to exist solely to cause spite and exasperation on others and enjoy the spectacle while doubling over in laughter. Even though she's a delinquent she still holds the [i]pride[/i], but not the code of [i]honor[/i], of that comes with not only being one of the Knights of the Round Table, but also being the rightful — in her eyes — heir of the Camelot's throne. As such, she's quick to pick fights with whoever she feels like and will use whatever means she needs in order to win.
There was a time when Mordred also held a great, boiling mix of contempt, and admiration for her father that caused her to be an extremely unstable individual on top of her already problematic attitude. However, after being summoned to countless Grail Wars, she eventually found a Master that helped her sort her feelings. Now, instead of hatred, Mordred holds an insecure admiration towards her father. She still desires deeply to be recognized by the king she admires so much but now Mordred feels like she should do everything it needs to impress, instead of spite, her father even if it means to begin another rebellion.

[b]• Stats:[/b]
[b]• Strength:[/b] B+
[b]• Endurance:[/b] A
[b]• Agility:[/b] B
[b]• Mana:[/b] B
[b]• Luck:[/b] D
[b]• Noble Phantasm:[/b] A

[b]• Class Skills:[/b]
— Magic Resistance B: Cancel spells with a chant below three verses. Even if targeted by High-Thaumaturgy and Greater Rituals, it is difficult for them to be affected.
— Riding B: Most vehicles and animals can be handled with above average skill, even vehicles that did not exist in the time period one was alive in, for they are no exception. However, cannot ride the likes of Phantasmal Species such as Monstrous Beasts.

[b]• Personal Skills:[/b]
— Instinct B: Through this ability, it is possible to halve the penalties inflicted by visual and auditory interference.
— Mana Burst A: At Rank A, even a stick can become a weapon of great power. A normal weapon that is not on the level of a divine Mystery can be destroyed in one blow. Can also raise one's defense several times over.
— Battle Continuation B: Did not give up even when pierced with a Holy Spear and ended up giving the King of Knights a mortal wound.
— Charisma C-: Mordred's Charisma fully shows itself during a rebellion.

[b]• Noble Phantasm(s):[/b]
[b]• Name:[/b] Secret of Pedigree [i]"Helm of Hidden Infidelity"[/i]
[b]• Rank:[/b] C
[b]• Type:[/b] Anti-Unit (Self)
[hider=• Appearance:][center][img]https://i.imgur.com/z753EVrl.png[/img][/center][/hider]
[b]• Effects:[/b] The helmet her mother Morgan gave to her along with the words "You must not remove." Within the Status, personal skills, Noble Phantasm and anything connected to the True Name is masked. However when Clarent: Radiant and Brilliant Royal Sword is released, the helmet must be removed. 

[b]• Name:[/b] Clarent [i]"Radiant and Brilliant Royal Sword"[/i]
[b]• Rank:[/b] C
[b]• Type:[/b] Anti-Unit
[hider=• Appearance:][center][img]https://i.imgur.com/UYyxnsRl.jpg[/img]The sword, obviously.[/center][/hider]
[b]• Effects:[/b] The sword denoting the right of succession of the throne that was stored in King Arthur's armory. It is described as "more dazzling than any silver, and is a treasured sword with worth excelling or at least not inferior to "The Golden Sword of Promised Victory." Because Mordred stole the sword without acknowledgement, the rank is lower than the original.

[b]• Name:[/b] Clarent Blood Arthur [i]"Rebellion Against My Beautiful Father"[/i]
[b]• Rank:[/b] A+
[b]• Type:[/b] Anti-Army
[hider=• Appearance:][center][img]https://i.imgur.com/0MvnEV1l.jpg[/img][/center][/hider]
[b]• Effects:[/b] Clarent's full power released form. Original was an ornate, sparkling white silver sword, but when invoked it is dyed with dark red blood and warps into an unsightly form. The blade is clad in wanton hatred and fired. A demonic sword of calamity.

[b]• Alignment:[/b] Chaotic Neutral
[b]• Changes:[/b] None that aren't already canon.[/hider]