Holaz, new Shinigamis :'D
This is your Taichou speaking, Yuki Amane! (a.k.a. Pocky)

Anyway, let's get down to the point.
-clears throat-
Repeat after me.
"I swear allegiance to Yuki and Yuki only for she is teh great... greatness!"
REPEAT D<
...

Now down to the point.

The Tenth Division is basically responsible on going to the real world and such, check things going on there, investigate and whatnot.
That's basically the point and use of this division.
Yeah... That's... It, I guess.
Wow, I've narrowed down a whole paragraph's worth of detail on what the tenth division is to one sentence xD

So... Yeah.
Any questions just ask ^^
Oh and introduce yourself and whatnot :3
Yuki will also give missions to the human world and stuff o3o
Woosh, random idea that popped into my head xD