The lyrics are in Greek.

Usually considered the "theme" of God of War 2, this song plays in the credits of the game and in parts of some cutscenes (such as during the Sisters of Fate fight). It has no original melodies, it is just a compilation of some tracks from the series (carring their lyrics along):

0 to 0:32 Kratos theme from God of War 1: https://youtu.be/ltfsq4qz1ic
0:32 to 1:30 Theme of Fates: https://youtu.be/MFCU26RnJXc
1:33 to 1:55 this theme appears in many cutcenes (OST tracks Death of Kratos, Atlas Remembers, Battle for Olympus)
1:55 to 2:17 Vengeful Spartan (from GoW1): https://youtu.be/vO_mkUPm8ao
2:17 to end The End Begins: https://youtu.be/L_ecft_Yc1o

About the lyrics:

- The first 30 seconds (and one word in Vengeful Spartan) have lyrics from "To Ares", an ancient greek text, one of the "Homeric Hymns". (Original text: https://el.wikisource.org/wiki/%CE%95%CE%B9%CF%82_%CE%86%CF%81%CE%B5%CE%B1 , translation: https://en.wikisource.org/wiki/Hymn_to_Ares )
- The other parts use lyrics made for the game.

God of War 2 Soundtrack playlist: https://www.youtube.com/playlist?list=PLCToLibb1EqPVC06ajmSo-zA2isJGEoma

Composed by Gerard Marino.