Tethys 1 is a free VST/standalone synthesizer.
Based on the architecture of the PAiA Proteus 1 (and in no way meant to sound like one.
I just really liked the simplicity of the design and the funky stepping program manger, unfortunately that drove hosts crazy so had to be left out.
As for its sound well its a 2 osc VA mono / 6 voice poly single ADSR, single LFO, single lowpass filter, limited to 4 glide settings and one of those is off so why do I love it, maybe because I don't have to decide which of a thousand different LFO waves to use, it has 2 and all the other options modern synths offer you to get lost in, basically its just fun, brash and easy to program.
P.S. can be very loud take care when starting it up.
Tethys 1 is available to download for free at Music-Society website (registration is required).