A Confidant (n.) is the person who gets the version that would end the friendship if it traveled.
A Confidant (n.) is one entrusted by A with the secrets ofB, confided to him by C.
A Kindred spirit (n.) is sometimes met only in the margin notes of a used book.
A Kindred spirit (n.) is a stranger who dislikes the same people you do.
A Kindred spirit (n.) is a stranger who laughs at the same wrong moment.
A Kindred spirit (n.) is someone whose silences land in the same places as yours.
An Old friend (n.) is someone you can go five years without calling and still owe twenty dollars.
An Old friend (n.) forgives you for things you have since stopped doing.
An Old friend (n.) picks up the argument you left off a decade ago, mid-sentence.
An Old friend (n.) is someone whose stories you have heard enough times to correct
An Online friend (n.) is closeness that never survives a shared airport.
An Online friend (n.) is someone who knows your midnight and not your face.
An Online friend (n.) is someone you would take a bullet for and would walk straight past in a queue.
An Online friend (n.) is a friendship with the logistics removed, and the logistics were most of the proof.