My Idea of a class, is a Necromancer Archetype.
Class Description of Soul Devourer Mage (name is not very good ^^;):
There are Necromancer that go on the 7th full moon every year on the Graveyard to search a fallen hero or villain. If the necromancer found him, he take the best parts of the body and extract from the muscles/ brain the "(Special)-moves and stored it in rune glasses.
The body part from what he extract this, is stored. After years - some say more than 40th, the Necromancer have from all the stored body parts a complete body, that he connects with magic to a vessel (like a golem).
After this step he wait for the 24 full moon of the year, and make from the extract "(Special)-moves a serum. On 12pm this serum must be drunk by the necromancer, to takes his life with this serum.His Soul go after that to the prepared Vessel, because the body of the heroes/ villains have a strong connection to the "extracts".
Now the "Soul Devourer Mage" have a new body and lost his necromancer-skills, but dont lose his mana. With the new body he won the Skills from the "extracts". Because not every heroe/villain have the same body/skills, the "Soul Devourer Mage" can be good in fighting and magic, or will be a much stronger Mage.
The special of this class is, that this body is dead - so he cant die. If he die, he only lost a extract/ bodypart and revive with lowered power.
The strongest of this class have waited many years to get more than 50th body parts....
Sorry for my bad english :/ I hope someone like this idea :)