Sirens was an unreleased video game developed as a proof of concept by Steve Ross and Joshua Gordon of Silo Productions in 1997. It is generally considered to have influenced or otherwise been linked to Blood Omen 2 as a precursor project. Despite frequent speculation, official comment has refuted concrete links between the titles and pointed to the influence of designer Steve Ross.
"Yeah, some of the themes are the same simply because they came from the same artist (me). As for the symbol I had completely forgotten about it being on one of the Chakan Sketches. I did about 20-30 full color concepts in 2 weeks and it was all kind of a blur"
"Jon thinks very highly of Steve's art, which he says he "loved bringing to life", and describes as having a signature feel — that there is always a common "look" running through it, much like how nearly any work by H.R. Giger is instantly identifiable as having been produced by Giger. He wouldn't be surprised if Steve Ross' art influenced Soul Reaver and future Kain games, but he also believes it's hard to avoid similarities in games about undead warriors, even if there are no intentional references to other works in the genre. Much like Steve Ross himself, Jon attributes any similarity between the Dreamcast Chakan concept art and Blood Omen 2 to that common "look", as opposed to intentional reuse."