That's definitely Clownpiece. Pretty cool remix... I think I recognize the singer's voice and the general style as well, but I don't remember what the band is called... they've done a lot of Touhou remixes.
listening to three albums by Tristania. they range from Gothic rock to Gothic heavy metal. Illumination is my favorite i think; Beyond the Veil is good; World of Glass is also good. there are a couple more albums that i can't pass judgment on because i haven't listened to them.