“That is not dead which can eternal lie,
And with strange aeons even death may die.”
You have no memory of who you are, but you have a vague recollection of your childhood and a hazy grasp on your early memories. What’s most disconcerting is that the last few years of your life are beyond your ability to recall, as if they never happened.
Despite this condition, you are still capable of performing all tasks normally. You discover that you still know how to use your class abilities. Access to your skills and feats are not hindered in the slightest, and you can inexplicably recall trivial information about the world that you knew before this condition took hold of you.
You might be initially inclined to forsake all other tasks in order to heal yourself of this state, but any attempts are in vain. Due to the unusual and powerful circumstances of your memory loss, nothing short of a wish or miracle can repair this damage, though your actions in future adventures may restore your fractured mind.