In "Keystone Motel" Steven says "you really are my favorite dad." In "Steven's Lion" Steven plays catch, a game that in TV has been shown to represent a father and son, with Lion.
In "Keystone Motel" Greg says that "we sometimes may hurt people while not intending to." and he looks away guiltily. This shows that something like that happened to him and Rose.
In "Open Book" Connie has a glove on her left hand and a sword. Rose was left handed and had a sword. It talked about Archimecerous being in love with "Rose"(Connie). It also talked about Archimecerous crying when Rose lost the sword and almost died. He cared about her. Steven dresses up as Archimecerous. He was a gem in a animal costume. Bismuth is a gem in an animal costume(not literally). Lion.
Lion tries to avoid Greg as shown in "Full Disclosure" when he leaps away after Greg pulls up. When they meet in "Ocean Gem" Greg makes a sound like"yooouu!" He knows Lion.
In "Lion 3: Straight to video" Rose had two arms and eyes. This shows that the love between her and Bismuth was mutual. She was pregnant while fused. That makes Bismuth partly Steven's father. Greg was jealous of that and that caused him to hurt Rose emotionally. He hurt her feelings by being angry at her and Bismuth for their love. Rose isn't from Earth so it may not be normal to us but it was for her. She thought it was okay to fall in love with others and that it wouldn't hurt Greg. Much like how Sapphire and Ruby were hurting each other unintentionally in "Keystone Motel".
All of this evidence points to Lion(Bismuth, the gem inside of Lion) being partly Steven's father.
VOUS LISEZ
Steven Universe Theories (Continued)
De TodoThis goes along with my previous theories! I hit the limit on the other book.