A true friend to me is someone who tells me what I need to hear, not what I want to hear- someone who's honest, knows how to keep their promise, watches my back, sticks up for me when necessary, doesn't gossip.
A kindred friend is the type of person I mentioned above, combined with someone who I can relate to on all levels. We share a sense of mutuality, resonance, common values, and most importantly, similar sense of humor. On a deeper level- we also talk about more relavent subjects of interest/current events.
I believe that the important ingredient in most relationships is having the ability to laugh with one another. Despite hardships, humor is a healthy way to release stress. If we share the same sense of humor, it lends a more genuine bond, a longer lasting friendship. It's the simple light-hearted moments that last a lifetime for me!