Holy crap I can't believed I found the anime! It's called Yamato Takeru, and in Chinese 魔天戰神. Google translates it to "God of War Magic days". :f6:
Both openings. 1st one where you see the blue haired guy with the katana is one of the main bad guys with the superior mech. 2nd video shows the hero's mech after it upgraded in a cocoon.
[video=youtube;k8AWY58inzc]http://www.youtube.com/watch?v=k8AWY58inzc[/video]
[video=youtube;90XlmYBGg38]http://www.youtube.com/watch?v=90XlmYBGg38&feature=related[/video]
I found out the anime is loosely based on a Japanese legend, and that the mechas in the anime are called Demon Air War Gods/Dark Sky Warriors and are bio-mechas. The main character's bio-mecha is called Susanoo, who is named after the Shinto God of the sea and storms. Sure is full of mythological/religious undertones in my childhood.
The only pictures of Susanoo I can find, along with another bio-mecha in the show, Tamanoo. It was initially piloted by a bad guy, but later one of the main character's friend pilots it instead.
Susanoo in base/first form
Susanoo in first form in comparison to Tamanoo
Susanoo as 2nd form in comparison with Tamanoo
Oh what the heck, there's a huge ass wiki for the anime:
http://en.wikipedia.org/wiki/Yamato_Takeru_%28anime%29
Now I just need to find the Catonese dubbed version of the show. I already found the original Japanese one. I'm disappoint it's most likely not subbed nor is it Cantonese, but it's still good enough for me.
*Found a fan art of Susanoo in base form