Throughout the Series
In Coup de Grâce, Echo is seen in a cage next to Bellamy Blake in Mount Weather. She quickly tells Bellamy "Quiet. They take the strongest" in Trigedasleng, which he doesn't understand. Echo calls Bellamy a "Sky person" and spits on him, she then has the alliance explained to her.
When Echo is nearly taken for harvesting, Bellamy save her by being "a live one". Echo then watches Bellamy be harvested and after Maya comes to rescue Bellamy, Echo helps to hold down Sargent Lovejoy as Bellamy chokes him. After his tracking chip is taken from is arm, he promised Echo he will come back her for her.