So as the title states i'm new to TES and in love with skyrim so far. I have 2 characters, one level 16 kajiit archer and a level 20 dark elf mage/necromancer. I know you can become a vampire and warewolf in game, but what else can you become? From what i hear, vamps arent all that great, and i haven't heard much about warewolves.

Those are the only two creatures but u can become an assassin for hire among other things. Also if you love this try oblivion.

So theres no way i can become a full fledged necromancer? Would filling up the conjuring tree be considered as such?

You can become a very powerful Necromancer.

You can get multiple undead servants that get very powerful. You raise the foes you slay letting them keep their equipment to use on your behalf. Enchant your Armor with conjuration extension to keep them around for a very long time.

You can get a very powerful blessing that allows you to raise all the dead in a large area around you. Very amazing to use.

Add in Fear, Paralysis, and Mayhem and you can own battles without raising a single hand in defense.