This set looks like GMK Kantharos (https://geekhack.org/index.php?topic=115920.0), and from what I can recall, many of the novelties and colours from that project are the same.
Did the design dispute by mixistor and arq1999 ever get resolved? I think that drama really stalled that project from getting any liftoff.
Regardless, I like the addition of special effects and pivot/focus on Hephaestus. Glad to see it come back reforged
I started working on Hephaestus as a personal project because I wanted to make use of GMK's new special effects in a project that actually benefited from them and didn't just use them because they were new, but I do have to say that the colors I imagined the set with from the beginning were very similar to those GMK Kantharos used.
As the project developed, at a certain point I wanted to pay homage to GMK Kantharos, since it was a set that I loved, but because of everything that happened around the set, it was almost impossible for it to ever come out. I continued developing Hephaestus until at one point I started thinking about whether it would be possible for me to acquire some of the novelties used in Kantharos, which is what I ended up doing (This is the reason why Angel is credited for the novelties, since the ISO Enter novelty and one of the 1u ones, which were not originally from Kantharos, were made by Stella).
At the end of the day, if I'm fully honest, Hephaestus is the combination of an idea/concept that I personally love, which is Greek mythology, and being able to pay homage to some extent (since the sublegends, alphas, accents and legends are considerably different from Kantharos) in a proper way to one of my favorite sets that never came out.