Something I like about the Souls series is the recurring characters or character archetypes and how each game handles each one differently. Solaire/Lucatiel/Anri, Lautrec/Creighton/Leonhard, Siegmeyer/Siegward, Patches/Pate, etc. But my favorite is also the simplest, and one of the first characters most players meet in each game.
In Demon’s Souls, this character debuts as the Crestfallen Warrior. Like the player character, the unnamed warrior had died and was brought to the Nexus as a spirit. He resents your host, the Monumental, for bringing him there, and offers basic guidance and background on characters and quests early in the game. The warrior is growing increasingly cynical and depressed as you speak with him, and when you give him news that his wife and daughter have been killed, he falls into despair, stops talking, and eventually fades away into nothingness.
This character archetype next appears in Dark Souls as the still-unnamed Crestfallen Knight. The knight, who like you is undead but has long since given up trying to fight his curse, informs you of what to do to progress in the early game and offers his opinions on other characters who have gathered in Firelink Shrine. As you bring more NPCs to Firelink, the knight starts to think the place is crowded and grows angrier at his own unsatisfactory situation. Finally he leaves, and when next you see him, in New Londo, the knight has given into his curse and become a ravening Hollow whom you are forced to kill.
In Dark Souls II, he becomes Crestfallen Saulden. Saulden tells you about Majula, the ramshackle community in which you find yourself, and points you toward the major bosses, but like past incarnations, he is sullen and is giving into despair. However, as new NPCs begin to populate Majula, Saulden starts to appreciate their company. In the end, he’s still depressed, but your actions inspire him to go on living. He is the only version of this character to survive.
Finally he becomes Hawkwood the Deserter in Dark Souls III. No longer crestfallen but still just as acrid, Hawkwood is a deserter from Farron’s Undead Legion who has taken up residence in this game’s Firelink Shrine. As before he drops hints about upcoming bosses and snarks about fellow Firelink Residents, but now he has an actual questline you can follow. A worshiper of dragons, Hawkwood requires your help on his pilgrimage to Archdragon Peak. Afterwards, he leaves a message for you to meet him in the Legion’s former base of operations. There, Hawkwood duels you for a dragon relic, and dies fighting for a cause he believes in.
What I love about this character(s) is how each game incrementally advances their development. He first gives into despair and fades into nothingness in Demon’s Souls, then loses his mind but retains his body in Dark Souls, finds a reason to live in Dark Souls II, and finally finds direction in life and dies with his mind intact in Dark Souls III. It’s a story of hope and redemption, and although it’s spread across four games and told through a background character, it’s one of the more uplifting stories in the whole Souls series.