~ My take on immortal inhuman humanoids and how to play the 2200 year old Faerie Monarch ~
Fey are self-centred at a deep level. For the fey "how they feel about a matter" is the most important consideration which makes them seem immature to humans. A fey lover is prone to jealousy and demands to know if you love them "most of all" and doesn’t accept that you can love more than one person equally in different ways – you must have a favourite!
They have strong autobiographical memory for things that happened to them and how they felt at particular times based on their emotions. Otherwise, the fey forget things they have heard or read if these things did not have particular importance for them. Such information passes from them as seasons change – though note that in the Faerie Lands (TM something else in a game company's product) seasons may last a long time and usually coincide with particular rulers.
Thus a fey may remember the mortal lover they lost centuries ago and the face and name of the killer, but the paltry details of the war that underlay the events causing their lover’s death will have faded. They won't even remember what mound used to be a city long ago if they had no emotional connection to that city.
Metagame - the fact long lived fey exist is not a "cheat" around the need for history skills and the fact that the past is often a mystery whose details are argued.
A fey who learned to master magic from dry books and lectures would forget what they learned when the Summer Queen displaces the Winter King upon the throne.
This has two immediate consequences.
The fey seek to intertwine learning anything important with passions and personal connections for they will then remember what they learn. Fey seek to learn from lovers and there is a natural tradition of intimacy between teacher and student. Alternatively, fey learn with the express purpose of gaining a lover, taking revenge of a foe or otherwise applying the knowledge and skill gained for an emotionally-charged purpose. What they learn in either fashion stays with them past the changing seasons and past the relationship in question.
Fey courts undergo massive changes when season-associated rule changes or some other factor shifts season. Power balances shift, plans are changed or forgotten where they were passionless amusements. There is thus a natural preference for the current season from those with status quo-investments and a natural desire to change the season from those with a poor position in the current scheme of things.
Metagame - this allows a Fey Player Character to exist, be very old, have plot hooks in dim past but not be a "cheat" as a walking library about historical events. Just have them be from a Fey Court where season changed in the past century.