From what I can see, I don't know the maker. Some knives are worth more by virtue of the name of the maker if it is an early work. That aside, it looks like a nice little knife design. It could be made from cable that has been welded. About the dark lines on the blade: I hope they are not bad welds. If they are not but just patina due to the topography of the layers, you probably have a good knife. If they are bad welds, I would not pay much for it unless I really liked the maker and may have some other factors leading me that way.
Does the knife have a reputation for holding a good edge? If so, it would make a great using knife.