Roland's Character Sheet
Roland's core concept is
Knows no actual magic whatsoever
Melee fighting, including stakes for heart-staking and blades for decapitation
Has the chutzpah and temerity to convince many folks that people they've known for years were secretly vampires or in league with same, and that he's bravely defended them
And your core question ...
Have Roland use a "magic artifact"
Make Roland have the normal class and character you want, but have him believe that some small trinket, say a religious icon on necklace, gives him the abilities he believes he has.
This could allow for some cool roleplay, maybe have him clasp it and close his eyes, or hold it to his forehead whenever he uses it. ...
Mark of Detection Half-Elf Artificer.
I'll start off by saying that your general character concept would not be welcome at any table I have ever played at, the same as any other character concept that seeks to actively sabotage the party's success.
That said, if you wanted to play an actually competent vampire hunter, I'd say that the Mark of Detection Half-...
If you go by character concept rather than exact plan: Bard or sorcerer.
Since bard and sorcerers rely on innate ability rather than actual training it meshes well with the idea that your character is mistaken about their skill with divination spells. They can use spells, and their non-divination spells work as expected. But when they think they are casting ...
Thomas Markov's answer is probably the closest you can get with player-focused material. The following is how I would normally handle a short-term character with specific requirements.
Roland uses an NPC stat block
A moderately experienced player will easily determine your class starting around level 3, unless you play extremely suboptimally.
"I'm an ...
I think what I've got here is the best solution to the problem as presented, but Red Orca's answer is the real solution I would recommend.
Roland is an Oath of Devotion paladin. Errr, he thinks he is.
The base paladin class comes with five divination spells:
detect evil and good
detect poison and disease
As a ...
There's always confusion about traits, because Pathfinder has chosen poor words for these two different kinds of traits.
The traits mentioned here, Chain Master & Pain Artist, are just a recommendation to take when you choose traits/drawbacks during character creation.
These traits are not related to (alternate) racial traits, which are part of your race ...
Adolescent elves do not have past-life memories while awake.
In the question, you wrote:
as adolescents, these memories begin to appear during their waking lives.
This is a misreading of the lore. First, we see:
During a young elf’s first few years, the memories evoked during trance are drawn not from current life experiences, but from the fantastic past ...
The question is if there is any official published material "in the history of the game". Well, I was a child and played when the whole D&D thing started (i.e. "Basic") to the 90's. So my wheelhouse is about the history and I can't answer anything about the rules and editions of the last 2 decades because I don't care for them.