I don't quite recall who, but I remember once seeing 'synpaths' being described as 'kin for fun, but for people who are already kin'. Which I suppose is true. However, for me, and my personal experience, that doesn't feel quite right. In KFF circles, 'kin' seems to be a synonym for the word 'stan'. And my synpaths definitely aren't the characters that I stan. I've also seen synpaths be referred to as one's personal set of 'blorbos', but that doesn't feel quite right either. Again, this implies that one views their synpaths through a very fannish lens, even if it does feel as if it implies more permanence. (At least, to me, it does.)
The coiner of the term describes it as follows: "Synpath is a tidy name for something you identify with on several levels, which could be a concept that resonates really strongly with you, an animal or mythological creature you feel you act like, or a person or character you share a lot of common behaviors with, among other things." This description has always felt more personal than KFF's "kins", or fandomgoer's blorbos. To me, my synpaths are things which I identify with, as well as things that are very important to me, how I view myself, and/or my life. Because of this, I've always felt that my synpaths have always been more telling to me, as a person, than my kintypes. My kintypes are not something I choose, after all. They're my past lives; they hold no bearings on who I am now. My synpaths, though, are entirely based off of who I am today, my experiences, and my interests.
On top of this, my synpaths are fewer in number than my kintypes. I currently have a total of seven synpaths, and, of those, four are fictional characters, two are animals, and one is a non-living thing. I am currently questioning two other synpaths, at the moment. Over the years, I've gotten quite good at recognizing a past life, but synpaths? I'm able to pick and choose those. I carefully curate exactly what things are important enough to me to label as a synpath, selecting only that which is closest to my heart, for the longest amount of time. A few times, I've seen something that I thought might be a synpath, but I made myself wait on it, to make sure it didn't fade away. Which, while I occasionally do for kintypes, I don't do for nearly as long or as often, because, again, I'm quite good at narrowing down the sensation of a past self.
My reasons for synpaths vary greatly from case to case. For example, Badeline from Celeste was the first synpath that I labeled as such, due to her story's incredibly intense effect on my life and how I view my mental health. The moon is the non-living synpath I mentioned earlier, because of the otherworldly connection with which I feel to it; she's important to me, because I identify with her and the stories about her, and have since a young age. Regarding animals, hyenas feel like family. I know so much about hyenas, and they feel familiar, in a way. Rounding things back with another fictional synpath, Lain from Serial Experiments Lain is one of my most recent synpath confirmations, by my memory. But she's so much like me, and I see myself in so much of both of her stories (the PS game and the anime). Her trauma and plights are unspeakably relatable, her rage cathartic, and there's just something about her that sticks in my mind. Like a sticker that you can keep picking at, but it doesn't peel off neatly. If you tried, you'd just be left with those torn, white bits of it, where you tried to take it off, still leaving their mark on your mind.
But I am not any of these things. Badeline helped me with how I treat myself, but I am not her. I see the moon as a friend, but I cannot say that I identify as her. Hyenas are familiar beings, but I could not say that I am one in a human's body. And my relationship to Lain is like that of a warped reflection (the same, but different). But the mirror is not one which shows my past lives. Just my current one.
So, no, I don't quite think that my synpaths are like KFF, or like my blorbos. More like fractured, cracked pieces of my current self, which I have found scattered across the world. I am not them. They are not me. But that is not the only way that something can be important to you.