God Eater 2 - Undercover

Main Story

God Eater: The Second Break
God Eater: The 2nd Break· GOD EATERーthe 2nd breakー
manga

God Eater continued 3 years after the burst.

Main Story

Пожиратель богов 2
God Eater 2· GOD EATER 2
manga

Three years after the event in God Eater Burst, a new fatal pandemic called the Black Plague caused by red rain has struck the Far East area. Members of Special Forces Blood, an affiliate of Fenrir who reside in a mobile base, are sent to assist.

Prequel

God Eater: Side by Side
GOD EATER -side by side-
manga

The story centers on Tatsumi Oomori, a God Eater, as a main protagonist along with the former 2nd Unit leader, Marco Donath, on their quest to annihilate all Aragami. (Source: God Eater Wiki, edited)