I've been looking and asking everyone and everywhere but I still can't find it, let me give you some details:
- Must be 90's or 80's, I saw it in the early 2000's in Italy, a country where movies and animes are aired many years after their first release in the West
- By the quality it seemed early 90's or even earlier than that, darker colours, themes and an overall serious tone, very dramatic at times
- The main character was a young man, not a teen, hairstyles and such were well, anime, but not dragonball style
- The main char and other people, both good and evil, could transform into what looks like a mech, mostly (if not only) wielding melee weapons, colourful energy blasts and such, but were not piloted mechs, they were mech-like after transforming
- The enemy masses were composed mainly by huge ammounts of green armored spiders or something similar, swords slashing through them would reveal organic tissue (purple I think)
- Battles took place in space, on Earth and possibly on other planets as well
- It does look a bit like early-Evangelion
- I remember only one significant scene: this woman-mecha character, somehow related to the protagonist, was defeated in battle by two other enemy mech-dudes, placed with her back onto a rock/mountain, her arms crossed on her chest, her hands pinned down onto the rock by two swords (perhaps her own), and she was executed by a powerful red blast. I remember it was very dramatic, one of the reasons I still remember this show yet without ever knowing its name.
It's been years that I've been trying to identify it, with no success, too many 80's series with actual pilotable mechs in them, I thank those who bothered with reading and I thank even more those who might solve my problem.