What requirements 2 unlock secret character in G-Net SnS?

[PC Engine Fan X!]

I have the Taito G-Card version of Shikigami No Shiro and was wondering what are the requirements need to "unlock" the hidden character in that particular game?

Yes, I do have the XS Game version of Mobile Light Force 2 for the PS2 console but would rather play the original Taito G-Card version even though it's presented entirely in Japanese kanji on the Taito G-Net arcade hardware setup.

BTW, is there a "Change Language" option on the Taito G-Net motherboard itself? (Would be cool if "English" language option setting could be selected...)

PC Engine Fan X! ^_~