Indy even for short I recommend you not to call it DS.
There are some that use it. Dark Souls and Deadly Sin.
When I looked at a forum. ( I don't remember.) I saw DS is a good game. I thought it was Dark Souls. But when I looked at the end it was Deadly Sin. So please I recommend you not to call it DS
lol They could, if they wanted to distinguish it from Deadly Sin... but I guess it doesn't matter one way or another people will know which game you are referring to... so go ahead and pick your favourite abbreviation!!!