Depends on what kind of introduction you'd prefer.
If you want an early variated album which already has most of their trademarks, and follow their evolution afterwards, start with
A Journey's End.
If you want a really-in-your-face-one, try
Spirit The Earth Aflame (my favourite btw
).
To The Nameless Dead and
Where Greater Men Have Fallen seem to be their most popular ones with peeps not too much into extreme metal, and they're great indeed.
Storm Before Calm is an underrated opus with some fantastic stuff on it,
The Gathering Wilderness has one of their greatest songs ever but little more, and
Exile Among The Ruins is an album I loved immediately but my impression is that it might be more for old fans like myself.
Imrama is a great album too, featuring their only song in Irish but I'm not sure it's the one to start with in 2021.
What say you,
@karljant ,
@Night Prowler,
@Perun , and all Primordial fans lurking on this forum?