Class Idea, Demonic Mutilator
I find the idea of thinking up interesting classes to be more fun than any realistic speculation, so I thought I'd add my own thoughts. Basically I was trying to think up a class idea that could rival the Necromancer in regards to being very dark and morbid, and I came up with this. I'm not completely happy with the name of Mutilator, but it works for now.
The general idea is the Mutilators are men who envy the demonic form and seek to gain the benefits of such a form. They are so bent on this that they do unthinkable things to their own bodies. A mutilator starts a normal looking human and over the course of the game slowly transform themselves into abominations that easily could be mistaken for a demon.
The skill trees would be Demonic Magic, Self-Transmutation, and Demon Grafting.
Demonic Magic skills are spells that the Mutilator has picked up during his study of demons. It would have a variety of magical skills with a dark and hellish theme. There would be a wide variety here, but the point is that these spells are mostly for support.
Examples:
Hellbolt: Unleash a projectile that deals fire and poison damage.
Darkness: The character is surrounded by a dark cloud that reduces the visible range of enemies and decreases their attack rating.
Summon Fallen: Call forth a fallen one and bind him to your will.
Blizzshock: The pink lightning as used by Council Members in d2.
Self-Transmutation is the art of magically changing your own body, and in this case those changes are of a monstrous type. These wouldn't be like so much like Druid transformations where you seem to switch into a completely different mode, instead they would be more like temporary stat-boosting skills and will alter your appearance slightly. Multiple transmutations could be applied at one time.
Protrusions: The character grows spikes and horns all over his body, causing attackers to take damage.
Launch Protrusions: Dislodge the protrustions you've grown and sling them at enemies.
Large Stature: Increases the size and mass of the character, slowing them but increasing life and damage.
Appendages: Long appendages grow out from the player, burrow underground, then reemerge to attack enemies. (Like Baal's appendages.)
Demon Grafting is where this character takes it's most odd twist. This is the art of removing the limb or organ of a demon and surgically planting it on your own body, often removing a human limb in order to do so. A lot of explanation is needed here, so bear with me.
The first part of this is harvesting an organ/limb. They may be removed from dead demons, and it's a pure luck as to what is still intact or can be successfully removed. Once you do remove it, that organ appears as an item in your inventory (in a little jar).
Organs have stats just like any other item. Each base type of organ has certain stats they tend to increase, such as a hand might have dex and damage, while a foot might have speed increases. Certain types of demons will add more stats based on the strengths and weaknesses of that demon. Some sort of ice-based demon might add a resistance to cold to any organ it drops. Organ stats will vary slightly in the same way that d2 uniques can have different %'s. A rare organ might have unexpected boosts.
Once you have your limb/organ, you can graft it to yourself to gain it's powers. Grafting an external limb will change your character's appearance appropriately. Grafts take damage and when they are hurt enough they will be rejected by the host body and die. In this sense they are like ethereal items. Each will have it's own level, with high skill levels needed to graft high level body parts.
Possible spots for grafting are listed below with examples of what particular types of demons could offer in that department.
hand/arm (str, dex, fast cast, claw attack),
foot/leg (speed, leaping),
tail/spine (thorns, tail attacks),
eyes (AR, infravision, apparent light radius)
teeth/fangs (bite attacks, life steal)
scalp/horns (charge attack, thorns, casting boosts)
heart (regen, life, mana)
Example skills:
Harvesting: Acts as a sort of MF for harvesting parts.
Graft [body part]: Allows grafting of higher level parts of this type.
Gracious Host: Decreases the rate of duration loss on body parts.
Demonic Infusion: Temporary effect. Take blood from a demon and inject it into your veins, gaining some boosts from that type of demon.