#1
So i've been l istening to a bunch of king diamond lately and listened to this song the eye of the witch, and there's a chord progression at one point of the song that i'm pretty sure i've heard in other metal songs like creeping death in metallica, now i'm very new to riff writing and what to know more about this type of progression as i would like to try incorporate it into my own music and use this type of progession or an alternation of it. Thanks!

here is the riff:

Riff 3
e|------------------------------------------------|
B|------------------------------------------------|
G|------------------------------------------------|
D|-7--7--7-10/12-12-12-12\10--7--7--7-7/8-8-8-8\5-|
A|-5--5--5--8/10-10-10-10\-8--5--5--5-5/6-6-6-6\3-|
E|------------------------------------------------|
#2
it's in D minor, using a bII... very common in metallica stuff, unless I'm mistaken

the whole progression is i (iii) IV (iii) i bII VII

the iii are in brackets cause I'm not sure if they are relevant or just passing tones