In the flashback at the beginning, Lex turned the sun red in a bid to depower Superman, a reference to the War of the Superman storyline in 2010, when he briefly turned the sun red to save Earth from an invasion of hostile Kryptonians. See more
Manchester was trying to show me what could happen if I continue to sit idly by. I have left you and Alex alone to face dangers. Is choosing the path of peace worth it if it means I could lose everyone I care about?
After what happened on Krypton, the way my mom stood by and did nothing, I've always sworn that if I can act, I will. But until you took your vow of peace, I didn't truly understand that simply by standing with someone you can make them feel braver. J'onn, the only reason Alex and I...