Prime

This is the Rick responsible for the deaths of Diane across all infinite realities and Beth from C-137's home dimension. Rick C-137 actively attempted to find and kill Rick Prime for approximately fifty years prior to the series' start and later in season six. Rick Prime's actions became the catalyst for Rick C-137's rise to power as the "Rickiest Rick." In Season 6, Episode 1, we learn that Prime is none other than Morty Smith's grandfather. And at the end of Season 6, Episode 10, we learn that he's supposedly from Prime's universe. At the end of season 6, episode 10, we are shown that Rick has returned to searching for Prime, and not wanting to involve Morty in this matter, he has replaced himself with a robot double. In Season 7, Episode 5, Rick C-137 (with some help from Evil Morty) manages to find Prime Rick. After a long and epic battle, Prime finds himself confined to a chair, unable to be reborn as a clone. Intoxicated by the prospect, Rick C-137 beats Prime to death... It's unknown what Prime did after killing Diane. Prime is likely the smartest Rick of all Ricks, which explains why he's outside the CCC. Prime is also such a genius that he created a weapon so advanced it doesn't even need a name, but the "loser" Ricks call it the "Omega Device."