Got Abyss Neptune to 99 yesterday and the Empress to 99 today. I am over 200 days in but I have spread myself around a fair amount. I am trying to change that now and focus on one monster per color at a time. Congrats on getting your Echidna!
So, here are my current options for leveling:
Freyr, the Blazing Swordsman (70) - leaning towards him, though Goemon is also a possibility
Goemon, the Thief (39)
Phoenix Knight Homura (55)
Earth-rending Emperor Siegfried (63)
I&I, the Twin Archers (16)
Awoken Hera-Is (33)
FD Lakshmi (72) - she is probably my next blue, or Siegfried
Fenrir Knight Kamui (56)
Wolf King Cu (92) - finish here then decide on Odin or Parv
Awoken Odin (53)
Parvati the Golden Goddess (70)
Rose Valk (54) - slowly but surely
Awoken Zeus (1)
Loki, the Finisher (72) - he's the dark target for now
Awoken Hera (47, 2nd one)
HQ Persephone (43)
Duke Vamp (53)
CDK (47)
I'm jealous. How long have you been working on those guys? I think it will take me all year to get one of my gods to 99 let alone 3. Been farming for Echidna for the last week and thought I almost had her when I saw something drop... much to my disapointment it was a treasure chest.