Been seriously digging GRAYCEON recently. Wondering if anyone could recommend some other metal bands [doesn't matter the subgenre] that feature prominently interplay between the guitar and some other instrument, like the Cello in Grayceon. And I mean serious interplay, as in counter-melodies, not just to provide another layer of sound, the way most black metal bands do with keyboards.

I'm already familiar with SIGH, so cross that one off the list.

Bride Adorned plays a very elaborate neo-classical take on progressive metal. It's got a rather gothic-baroque tocatta feel to it. The album Blessed Stillness is the one I own. Lots of interaction between the guitars and keyboard.

If you're looking for bands that do this with instruments other than a keyboard though, I understand.

A bit too frilly sounding for me, but sort of on the right track. Was hoping for more actual orchestral instruments, rather than synths, though.

Alright, that does narrow it down considerably but makes for a more challenging and fun inquest. I'll see if I can recall anything else.

I assume you know of Sear Bliss? They use the trumpet very often in their songs, often as a major melodic voice.