Originally Posted by
Cobblemaniac
It will boost the odds of you getting Satan. In a normal gacha your odds are (3 / 2 / number of SSR himes available)%, so it's pretty much sub 0.1%. This one simply guarantees that if you get an SSR, it will be Satan's release weapon. Assuming it's the base 3% rate, that's a 3% chance of getting Satan.
It is an event. On DMM version, it came 2nd Feb this year, so we can anticipate it to be around the same time next year.
LB mats? If you mean bricks, those aren't just for eyes, they can limit break everything up to SSR weapons. Includes event (you shouldn't), hime (might be worth, check DMM wiki to see which ones are worth) and DE weapons.
You need 10k tower points to grab the brick (+ books but that's irrelevant), but to describe the tower event requires another thread all on it's own, so maybe someone will do it another day (I'm lazy as all fuck). Spoilers: the content is a fucking nightmare to deal with.
As far as the event spacing goes... I think tower happens every 2 months or so.