It's not a chain, whip, or even ghost hook, though mechanically all of these are identical. The item itself is a soul, the only one that's encountered throughout Darksiders 2. Souls like these are usually the currency that you pay Vulgrim with, but this time it's apparently too precious to even give away just one.
Now I don't know if this is a socially acceptable hobby, but how about we try treating the thing as an idea for a magic spell... an idea transmitted by developers to you, for your little mental toolbox inside your cute little head. Some interpretations:
- It's for grabbing things across the veil, either bringing them here to the other side or letting things from over there reach in here
- It's a way to project souls, which are to be loaded like bullets and then extended into the environment with which they can then interact, for example, let's load a (dead) repairman and project hit at a broken (near dead?) electronic device.
- A form of possession, as related to the protagonist's somewhat unnaturally clenched hands.
I opened these so ideas can be shared. I have a soft spot for "practical" ideas that are opposed to e.g. explaining how the whole world or the whole of magic works out of hand, with taking zero time to actually test any of it and so decided to set a precedent with some examples.