There are multiple bands with this name:

1) Abyssal is an atmospheric blackened death/doom metal band from the UK. Since forming in 2011, they have released three full-lengths. They are currently signed to Profound Lore Records.

Their music will likely appeal to fans of Mitochondrion, Ævangelist, Desolate Shrine, Portal, Impetuous Ritual, Embrace of Thorns, Auroch, and/or Bölzer.

Bandcamp: http://abyssal-home.bandcamp.com/
Bigcartel: http://abyssal.bigcartel.com/

2) Abyssal is a Black Metal band from Sweden.

3) Abyssal is a Thrash Metal band from Brazil.

4) Abyssal is a Punk band from UK

5) Abyssal was a black metal band from Finland.

6) Abyssal is a death metal band from France.

7) Abyssal is a post-metal/funeral doom/sludge metal band from Tijuana, Mexico. They changed their name to be with all caps and spaces, A B Y S S A L.
Bandcamp: http://abyssaltj.bandcamp.com/

8) Abyssal is a dark ambient/drone project of Dutch producer TREVØR. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.