The Cycle Magics are broken up into two parts, Life and Death. All living creatures are born with a soul, this is fact. If a creature no longer has a soul , then it's dead. When casting this kind of magic one thing determines what can be cast.
Life magic always requires a soul. In all cases it is your own. Your own soul replenishes, sop casting spells doesn't harm you, but will instead drain you. Just like muscles to wield more magic you must "flex" your soul to make it stronger. When a spell is cast, it varies from person to person. Some people just have stronger soul, so they are able to cast spells while many others are too weak and as a result can't cast life magic. There are two main forms which are formed based on two ways of thinking, logic and emotion. Logic is the most common and most all spells will appear blue. This form tends to be more defensive and as a result will preform better defensive spells then with someone with an emotion form. The Emotion form isn't as common and will appear as a red when a spell is cast. The form is very combative and will preform offensive spells with more ease and potency. It is possible to change ones form, but this takes time since it's a change in your soul, which is a change of who you are.
Death Magic on the other hand still requires a soul, but instead of your own, you would use someone else. This however is near impossible to accomplish. When casting magic, you will always tap into your own soul. To create death magic, you must burn away the magic from a soul without it replenishing. In a way, you must kill a soul. This would harm the user and result in your own death and no spell. Trying to mess with another person's soul will result in them "touching" this will still repair the soul and not destroy it in a manner that it need to occur. Death magic requires such a specific way to occur that it's physically impossible a living creature to use it. This also means that if a creature became undead then they would be able to use such a magic.
In either from the results are the same. Spells can range from anything you can imagine. Throw lighting bolts or raise a huge magic rock wall. To accomplish spells with reliability, tomes are used to do this. Otherwise a spells could have very unintended affects. in this way, possibilities are endless as long as there is enough energy to cast the spell.
While Life Magic it is naturally occurring it's difficult to collect other then the one you obtain upon birth. Everyone gets a soul, their source of life magic. Depending on the type of soul with determine the color of the magic used. Typically this could be a dark red or to a light blue.
Death magic is naturally occurring in only one instance. When the body or physical form of a creature dies it release the soul attached to it. During this time the Soul must spend the energy to leave and as a result creates come death magic. It's only in this time actual death magic occurs. This magic appears to use as a green aura or ooze.