I know some spells to unseal/release/summon Demons and use their powers. They are not just for battle. You can use one to make someone fall in love with ya and increase their lust so you can protect your marriage. And there are more advantages...
But the souls who work behind the spells are from darkness like Lucifer, Leviathan, Satan, Belphegor, Mammon, Belzebub, Asmodeus, Lilith, Lamatu, etc.
-These spells have no taboo.
-They do not harm you if you cast them wrong. You just need to recast them again.
-If you could see the demons you saw no scary faces.
-You do not need to sacrifice lives for the rituals.
-You do not lose control when you own the spells.
-Your house won't be haunted after you used them.