SkunkyArt | WTFBOOOMSH — Artoria Pendragon vs Darth Vader

Both are the "Chosen One" of the verse, who were born in a very odd time within the story, contrasted with one another (Artoria being born within the Dark Ages and Anakin was born in The Great Peace) and were destined to fight the opposing force of the world (Artoria being the Red Dragon to destroy the White Dragon and Vader being the Jedi who would destroy the Sith).

Both had unusual conceptions leading to their immense power and position as Chosen One (Artoria being conceived by the concept of the Red Dragon that protects Britain via magic and Anakin being conceived by Midi-Chlorians) with even the state of their births being a surprised (Artoria being born as a woman and Anakin being a virgin birth).

However, despite this they lived a fairly humble life at the start (Artoria being raised by Merlin (and later Sir Hector) in a small village and Anakin being raised on Tatooine by Shmi) and didn't know of their destiny (Artoria being raised as a knight and Anakin being a slave) before finally realizing their chosen path (Artoria pulling the Sword from the Stone and Anakin being taken in by the Jedi Republic) where they would gain their legendary blades (Excalibur and Anakin's Lightsaber respectively).

Both had smartass mentors (Merlin and Obi-Wan respectively) and led what were considered some of the greatest warriors of their time (Knights of the Round Table and The 501st legion), as well as having a follower of their order that very much looked up to them, until later they came to blows after their fall (Mordred and Ahsoka respectively).

Their ultimate falls were kickstarted by their wives being in a forbidden relationship (Padme with Anakin himself and Guinevere with Lancelot) with these falls taking their respective societies that they were supposed to protect with them (Camelot and The Galactic Republic).

After a climactic battle with somebody they used to call their ally, both were fatally wounded and lost their weapons, before being brought back from the brink by another being (The World and Palpatine) that somehow changed them (Artoria becoming a physical Heroic Spirit and Anakin becoming Darth Vader).

Both would become servants to a man who saw them as little more than a tool who they grew to hate (Kiritsugu and Palpatine), now being akin to a shell with little more than regrets left.

Both would eventually be helped in their redemption by a young hero that never gave up on them (Shirou Emiya and Luke Skywalker), with said hero also coincidentally using one of their previous weapons at one point (Shirou projecting Caliburn and Luke using Anakin's lightsaber).

After their final deaths, they would continue to help the side of good from beyond the grave (a Servant replica of Artoria from the Throne of Heroes would assist Chaldea and Anakin would continue helping the Jedi as a Force Ghost).