Fate Grand Order: The Samurai Pendragon

Artoria Famously known for having the blade gifted to her by the lady of the lake known as Excaliber the Blade of Victory.

Mordred the bastard son who had Clarent a sword passed on from Uther. Artoria's Father and killed The Lion king during the battle of Camlann.

What if there was another Pendragon related to them and was Kept a Deep secret for generations
to come until chaldea Arrived?