How about a picture?
What you're describing does not sound like an OEM part - the Samurai does not come with a little black starter relay, although some owners add one in an attempt to fix a problem with the starter, and it also does not sound like an ignitor - removing the ignitor should also not prevent the engine from cranking.
It might also help if you told us what the problem you're experiencing is - if I were to assume that what you're looking at is a relay that someone added, and since you say it won't crank without it, I would assume that it cranks with it, so it sounds like it's working.