Welsh Lyrics:

Gafflwn Dihenydd O’r fuddugol yn wiriol sydd,
Ni fydd neb yn ein drechu,
Falch ydy ni I drochu,
Traed o flaen I’r Annwn,
mewn y gwybodaeth fe godwn ni.

English Translation:

We cheat Death from his rightful victory.
No one can defeat us,
we are glad to plunge feet first into Annwn
in the knowledge that we will rise.

Annwn is the afterlife/otherworld of Welsh Mythology. Basically, it's heaven as it was essentially a world of delights and eternal youth where disease was absent and food was ever-abundant.

This is the soundtrack heard on the tv spot of halo 3 odst and this is the greatest trailer ive ever seen in 2008 it was cool it made me want to play halo i …