Sera is a good person but she is bad for herself, her obsession with Erin is fucked up.
Ok maybe it going to a obsession with Mars is also bad but its unironically healthier for her ( barring losing the eye) and the dude actually likes her romantically if you don't lie to her
As for Elena its true, that one was peak evil Mars
Could make the same case about Elena being bad for herself. She blames herself for Mars's mom getting killed and putting his life on a fucked up trajectory. Her penance for it is becoming Mars's cock slave.
At the end of her current route Mars does genuinely like her as well if you choose the +relationship choice, hurting her like that pretty well broke him. Not saying it wasn't absolutely fucking evil, but there's layers of culpability here and Mars's net contribution to the evil is maybe 5% between the goddess and Elena's brother's(??? I forget, it was her brother who killed Mars's mom right?) contribution.
Then Lavinia is pretty fucked up but you have to love her as she is. Erin is pretty fucked up but a lot of that comes down to the fucked up goddess and his upbringing. The side girls are fucked beyond belief but then again they're all victims of Hilda so they get a pass.
Not sure I agree with the original persons claim that the girls are worse than mars, Cecille notwithstanding, but they are all about as fucked up as him.