Character = a harmonious union of a number of well-defined and known virtues: courage, prudence, humility, magnanimity, modesty, justice, etc.
Self = a collection and solidification of permanent pleasures, interests, loves, projects, and life’s works.
Personality = character + self = the virtue trinity.
Persona = social roles, such as one’s job, public accomplishments, objects of pride.
Character is built, self is discovered.
It may be asked, if one (though not the overriding) purpose of life is soul-making, why would not God create us with perfect character and full self-knowledge? Because the process of character-building and self-discovery is everlasting. There is no such thing as a fully completed human soul. Might as well start at zero.
Id = desire (potency) / enjoyment (act) in the narrow happiness trinity.
Ego = intellect + power in the happiness trinity.
Superego = demands of natural law in the nature trinity and self-imposed ideals in the virtue trinity.
Personality grounds pursuit of happiness, because one seeks the happiness made proper to himself by his self. These pleasures will not be undone in the future. But both virtue and happiness trinities are in a flux, at the very least in constant development. So they may be aligned well at t1 and misaligned later at t2. Ideally, the process of harmonizing pursuit of 1st-order pleasures with development of personality (and in addition with improvement in nature such as learning to love) is always proceeding and effective.
The key advantage of getting a self is that without it, commitments to long-term projects are problematic, because of the spiritual chaos in one’s heart. It makes no sense for me to embark upon complex and long endeavors, if today I like X, tomorrow I dislike X. I begin a task and abandon it only a little later. I’m a “quitter.” So my pleasures are of a primitive kind capable of being immediately satisfied: food, sex, games, and the like.
Moreover, while a long-term goal is being achieved, all one does is pay the costs of it. The revenues lie far in the future. A person without a self, even if he resolved to see a project to its end, may find the present pain unjustified by the future pleasure and again, quit.
Development of self is organic, as change-amidst-permanence, so there is always a core self, even if it grows more interesting and complex with time.