Your friend may be immensely appealing to you, but they will also provoke deep feelings of insecurity, aggression, suspicion or jealousy within you. Their vitality and independence will play off your deepest insecurities and run directly counter to your own inner source of power. This will be an intense relationship, no two ways about it.
It could also be quite transformative, but probably not without some strife. Unconsciously, you'll try to transform yourself by projecting all your deepest suspicions and anxieties onto your buddy and then fighting against them; but this treatment will be utterly unfair. It's not their fault that they'll be a stand-in for everything bad that's ever happened to you! You'll have a hard time seeing that their intentions are pure. Your behavior is likely to push your friend away, but all of this could actually have a positive outcome if it forces you to learn to let your buddy be the person they are. But that's a big 'if,' and it will take a great deal of effort and self-awareness on your part.