I was thinking of a way to make playing a magic character more interesting from a role-playing aspect. What are some ideas you have?

A Blood Mage sounds cool, investing into health instead of magicka, but the spell required to convert health to magicka is incredibly rare and hard to obtain - am I right?

Well, there is only one place to get it but if you follow the College quests, you'll walk right by it.

Isn't the dungeon it is within quite hard though? Like, something you can't do at a low level?

Play as a Mad Mage.
Use alteration, illusion, restoration and destruction.

Use spells like mayhem to make enemies kill each other then kill the last enemy with a blast of fire.

My idea was a Blood Mage. They go to the College to train in magic, but during said quests discover the Equilibrium spell. They later become cannibals to feed their blood lust and use it to make more magicka for more spells.

It could work. The dungeon it's in is difficult but not the hardest in the game. I usually do it at level 15ish but it's possible at lower levels if you're focused.

I play a Sorcerer. Most fun mage I have. Conjuration, Alteration, and Illusion will be your 3 main skills. Muffle will help with your sneak since you wont be putting anything into that, but will be using it. Get to the Silent Casting perk as quickly as you can with this build. It will certainly help.

The idea is to use summons to do your dirty work for you. Alteration is there just in case you get into a sticky situation. Illusion is to help you with those larger groups of enemies; either calming or frenzying them (Protip: Calm the first, then frenzy them after you've gotten some distance away, and, preferably, hidden yourself so they don't attack you too.).

This build is especially fun when you get enough magic to be able to cast invisibility alongside spells such as frenzy. You'll have no combat skills to speak of, but your Illusion and Conjuration should more than make up for that.

I've seen the bloodmage idea before too. Been meaning to try that out for myself on an argonian since they have Histkin. This could theoretically give you infinite magic for the duration of Histskin.

The difficulty of a Blood Mage is that you couldn't really begin role-playing as one until you ahd the appropriate spell, which is quite a challenge at a very low level to obtain.

My latest character is by far the most fun I have in all of my 25 plus characters in Skyrim.

Name: Tai Lung, Dragonwarrior Chi Master

Race: Khajiit. Made to look like Tai Lung from Kung Fu Panda

Skills: Unarmed Empty Hand Build (close range attacks); Shock Destruction for ranged Chi transmission attacks; Alteration - for Dragonwarrior chi armor.

Equipment: 6 stacked heavy gauntlets each enchanted with +10 unarmed damage, one hide gauntlet enchanted with +10 unarmed. Ring of Namira. Amulet of Talos. Ragged robes.

Tai Lung is primarily an unarmed build, using his bare hands primarily to deal damage. But with years of chi training he has become a master of shock magic and alteration chi armor. He is evil and wants to prove to all of Tamriel that he is the most powerful Dragonborn/Dragonwarrior who ever lived. He carries no weapons, and carries no staff. Only his bare hands/claws and destruction magic is what he uses.

By FAR the most fun Ive had in Skyrim.

Will Equibrillium fortify your magicka above your max, or just refill it? If it won't fortify your magicka above your max, that would put a serious cramp in a prospective blood mage's style.

Refill.

That sounds quiet interesting. An unarmed character with a mastery over one single element, such as fire.

Like in the films, punch people and hurl fireballs.