Become a vampire/mermaid.

k, i agree with you FallenStar, but i'd like to point some stuff out.

yes, there is no spell that can change you, magic does not work that way. however, there are types of vampires i'll agree with, psi vampires. they 'feed' off other peoples aura/energy. i think it's possible to train yourself to do that, but there's no other way to become a vampire. werewolfs no spell will work. that being said, some people have the spirit of an animal, or an animals soul if you will, so they feel connected with a particular animal. they do not change into the animal, they've just got a strong bond with them. again, a spell will not work, you are born that way, it cannot be changed through magic. it can be changed through costly surgery, but i don't recommend that.

meremaids and faeries i have never heard of someone being born with a spirit of one of these, so i don't think anyone can be one.

if you feel connected to a vampire, werewolf, meremaid, faerie or whatever, study their magic. i've always felt a strong connection with dragons, i don't want to become a dragon, i study their magic, their wisdom, their history. if you want to be a vampire, look into blood magic. there's fae magic, and i've seen tarot decks of all of these creatures.

You 'cannot' be a mermaid BUT vampyres are different. They are 'possessed' people who do not 'realize' that there is a 'spirit/demon inside of them that 'feeds' on blood. This is NOT a nice existence as first you don't know your possessed. Second your NOT in control. Thirdly when it's 'over' and yes this spirit will eventually leave when its either done with you OR your body can no longer 'tolerate' the blood ( human bodies were NOT meant to ingest blood. You WILL get violently ill eventually) then you will NOT know what happened or how long you've been 'used'......