When I get bored, I get bored but jeez how bored am I~
ANYWAY. I figured I should write a quick explanation about somethings about Stein and other Soul Eater characters' abilities!
So to start out with, everything has to do with soul in Soul Eater. And by soul, I mean like spiritual energy, the thing that make you you, etc, etc...
Essentially one can cultivate their soul in order to make themselves stronger and more adept to other areas of experience. Such as fighting or seeing souls. Death the Kid uses his abundance of spiritual power--aka soul wavelength--thanks to his shinigami heritage to fire "bullets" with Liz and Patty, his weapons. Maka, on the other hand, bonds with her partner Soul (who turns into a scythe) through their wavelengths but doesn't directly put power into her weapon like Kid. Instead she's more suitable for the kind of thing like studying the opponent, getting a feel for their strengths and weaknesses because she can see their souls.
Technicians and weapons have a unique bond because of soul wavelengths. If they have wavelengths that don't sync up (like Black*Star and Soul, for instance), they will fail miserably. If they have wavelengths that are compatible with each other (say like Black*Star's "I AM GOING TO SURPASS GOD AND AM #1!" personality with Tsubaki's submissive and accepting personality), you get a pretty good, strong team and are better able to get to the next stage in power and such.
A person can also use their soul wavelength as a weapon in and of itself. Black*Star is quite good at this form of attack, where he compresses and then expells his own soul's wavelength into another person, attacking them in the soul rather than the body. It's far more effective of an attack but more difficult to accomplish unless you're a more focused or stronger individual. Maka, for instance, would have a more difficult time doing such a thing because she hasn't trained for it unlike Black*Star who is insane about that sort of thing.
How does Stein fit into all of this?
Simply, he's capable of doing all of the above and then some.
Stein himself is a genius technician/meister who can pretty much stand on his own without even a weapon because his wavelength attacks are so strong. Probably because he's got a pretty powerful soul to begin with (see icon for Maka's viewing of said soul). When first meeting Maka and Black*Star along with their weapons Soul and Tsubaki, Stein appears to be this kind of spacy, klutzy sort of person speeding along in his roll-y chair and falling over whenever he hits the door stop. However, the first blow from Black*Star which Stein easily blocks even while sitting in a chair shows that he isn't a slouch when it comes to fighting.
Stein also uses these wavelength attacks to purge things from people's bodies or do things like stitch other people (or himself) to the ground so they can't dodge or escape his other attacks.
Like I said, he's a genius technician and as thus, once had a weapon when he was younger. Before meeting Maka's mom, Spirit (now known as Death Scythe) was Stein's weapon and senpai. During the present series, they fight together against enemies more than once and form a formidable team in which Stein uses Death Scythe as 1) a shield and 2) a longer-ranged attack while also keeping a free hand open to use soul attacks on the opponent. Also, if you think about it, this means that Death Scythe is able to bond with Stein through soul wavelengths which means he understands Stein probably the best as well as accept him for the crazy person he is.
... even though Stein routinely experimented on Spirit during the five years they were partners at school.
Stein is also very keen in seeing other people's souls, able to see far more detail in a person's soul than Maka, who is just beginning to really hone her skills, is able.
And basically that's all I have for right now. Basically, in summary, just because Stein doesn't look like much and seems to just be a mad scientist, doesn't mean he doesn't have a few tricks up his sleeve. Ditto for the other Soul Eater castmates.
There's a fine line between genius and insanity and Stein just totally ignores the line altogether, pretty much.
Stay tuned for another post some day soon about Stein and his flimsy sanity!