Hi there!Well, firstly, Shinto is a way of living moreso than a religion. One of the cores of Shinto is to live with oharae, or purification, or keeping the balance between purity (oharae) and impurity (kegare). It’s important to remember purity doesn’t mean “good, clean”, and impurity is “bad, dirty”. Think of them like positive/negative emotions/feelings/energy. Positive energy (Purity, Oharae) makes us feel “cleaner, energetic, happy”. - it’s “pure” because in Shinto thinking, our spirits naturally at birth are very positive, innocent, joyful (nigimitama, kushimitama, sakimitama). When this naturally clear spirit is clouded by Negative energy (impurities, kegare), it loses some of that original purity - so that’s why we go to the shrine, or practice faith in Kami, and do purification (oharae) ritual daily, to restore to that natural pure spirit. Negative energy (Impurities, Kegare) makes us feel “angry, sad, down, bitter”. However, negative energy isn’t always bad. It’s natural, and important to feel out these negative emotions too - these “impurities”, it’s a natural part of the Universe/Nature, and thus not “unnatural”, “an offense against nature (tsumi/sin)” or “bad/evil”. In fact, even Kami themselves are prone to kegare/impurities, and thus also do oharae, like people do. When a spirit is feeling negative, angry, rough, rude - it’s referred to as “aramitama” or rough spirit.It’s thought in Shinto, every being - person, kami - anything with a spirit/soul, has a single spirit/soul, but then four “aspects” or “souls” of that, that can manifest individually as well, but still part of one connection. This is Nigi, Kushi, Saki, and Ara mitama. Therefore, kegare in a sense is natural, we just need to keep a balance, in day to day Shinto living, and way of life.You can read more here: https://en.wikipedia.org/wiki/Mitamahttp://eos.kokugakuin.ac.jp/modules/xwords/entry.php?entryID=1181Now, when kegare is overwhelming to us, when negative energy consume us and get the better of us, we let that control us and overtake us. This is known as “tsumi” or translated as “sin” - but in a sense it’s more like an “offense against the laws of the Universe, offense against nature and yourself.” Tsumi is like killing someone, out of rage or hate, for example. That’s why, it’s important to keep the amount of kegare/negative energy constantly purified day to day, because it’s easy to accumulate, especially in our modern society which tends to get very negative. This is all traditional Shinto thinking, way back from the Jomon and Yayoi periods. Original Japanese thinking/interpretation of Shinto. This is why things like childbirth, menstrual blood, blood, illness, death was kegare. Not physically, but because…childbirth is painful and tiring (pain = bad energy/feeling, tiredness = not energetic )menstural blood (periods = painful, tiring, stress from not being able to work as usual, etc) blood (when blood is spilled, usually there is physical pain, or they are being treated for an illness by a doctor, or worse, someone has killed another, etc.) illness (well….you can see why)death (of course, because it causes immense grief and sadness, and conducting funeral rites, mourning, and so on…) It’s less about the physical aspects , but more about the emotional/psychological/how it affects our spirits.That’s why in myth, the sources of kegare were moreso the emotional turmoil. It wasn’t Izanami no Mikoto-sama’s corpse that was impure, it was all her hatred and rage (kegare) to Izanagi no Mikoto-sama’s fear (also kegare). Amaterasu Omikami-sama was not scared by the blood of the skinned horse, or the death of her younger sister (Wakahirume no Mikoto-sama) alone, it was the grief of the death of her sister, and the shock and trauma (kegare). If it was physical, she would have hid in the cave when Susanoo no Mikoto-sama threw excrement all over the palace - but she was able to brush it aside, it wasn’t a big deal to her. But when things cause real kegare (grief, trauma, fear, rage, anger), that is when problems arise. And also, that is why Ame no Uzume no Mikoto-sama’s dance (with joy, happiness, laughter, revelry) was Oharae/Purification and brought out Amaterasu Omikami-sama again. Now, all that being said….to your question, well,Personally, given all I explained, I don’t see it as impure or bad. You should be respectful of course - but if you work with Shinigami or Death spirits in balance, and it is as a way to bring peace to those who passed on, or to ease grief and sadness of death, or strike a balance /understanding death as a natural part of life/the Universe, this is Shinto way/thinking. You can worship/work with Shinigami without keeping this in mind, but then it’s not Shinto - it’s just spiritwork with Shinigami. Even so, in Shinto it can still be a grey area to some….because Some priests and people believe the later thinking/traditions, who feel physical things /aspects are impure. The view is the Asuka to Heian era influenced beliefs, when Shinto mixed with Chinese and Korean culture, and as a result Taoism, Confucianism, and Buddhism. In this tradition, it would be impure, because “Death” itself is seen as impure, not the energy/emotions surrounding it, and not good to deal with. But in these times lately, Shinto is moreso going back to that ancient/original belief system, and personally I feel it makes more sense, given the context of the myths and practices/rituals. This is why more and more shrines are also handling Shinto funerals, and offering Mitama (spirits of the deceased) home shrines in Shinto style (called Soreisha), and so on. I hope this could help!
