Possibly the quintessential Marco black metal album, Ashes Against the Grain by Agalloch is a true masterpiece of atmospheric black metal with post-rock and shoegaze elements. I'm 99% sure that Marco would have no trouble at all listening to this and that he might actually enjoy it during a forest trip. After all, the music is as far removed from black metal as possible, with only the tremolo riffs reminding us of its ancient ancestry, as well as the slightly growled vocals, which are more soothing instead of grim and threatening. Also, there are is no obnoxious Satanic imagery to be found here. Only blissful lyrics about nature, mountains, lakes, forest and walking naked through the snow. It's okay, Marco, there's nothing to be afraid of.
I might see them live in about three weeks or so. If I do, I'll be sure to write a long-winded report of that magical evening. Until then, I leave you with their bandcamp page. Shhh... no tears, only dreams now.