The negative and corrupted aura around Jormundgander grew stronger as he experienced more and more of those lives. The guilt overflowed his soul, changing his idea of himself as a warrior into an evil monster.
Jormundgander understood that those feelings of love when he saw sisters, descendants, lovers, or sons did not belong to him, but that did not change anything.
Every time his younger self killed someone, he experienced his victims' anguish, sadness, and hatred. He screamed with all his power in every life, trying to change things, to make it stop, but nothing worked.
Venganza and Ira stared at the Leviathan Primarch, and each could feel the torment this one experienced. Although they felt sorry, they were also happy.