I practice the Vampyric aspect of Necromancy; basically it is equivalent to a leech, but instead of blood, its their energy.
There's two parts to it though, I've only been able to do the basic part which is sap energy from people using my hands to focus the leech - if you can master that bit, then the advanced part shouldn't difficult, but unfortunately for me I've not mastered it.
The advanced part of it carries a lot more risk & rewards than the basic part; instead of drawing energy from people, you're suppose to extend your spirit partially from your body an use it to latch on to someone else's spirit (the person you're doing it to has to be living though), then you're to take part of their essence to enhance your own.
The Reward: If you chose the right kind of person, your physical & spiritual parts of you will become much stronger, in order to gain more you'll have to find someone who is stronger than the one you just leeched from.
The Risk: If you choose the wrong kind of person, you'll make yourself weaker in both physical & spiritual senses. Also, if you sap too much, you can inadvertently cause that person to die and the part you took will become a never-ending reminder of what you've done.
If you can do the advanced part of Vampyric Necromancy with no real screw ups, you could feasibly make yourself live longer.
There are other Aspects, and even this is considered one the harder aspects, I just can't see myself doing a different one.
