Like…this wasn’t about Emori becoming the Commander of Death. This was about Emori controlling Clarke. In telling her (probably true) story she successfully played on Clarke’s soft side, the she played on Clarke’s need for vengeance (because even though Clarke’s never taken a life for revenge, she’s definitely acted out of a desire to hurt those who have hurt her before), and then she beat a man tied to a chair right in front of Clarke (who has a soft heart but understands vengeance) as one final move on the chess board.
Emori has learned what so many other Grounders didn’t understand in Season 3. You don’t have to kill Wanheda to absorb her power. You just need to know what buttons to push and Emori, who has been a survivor her entire life, played Clarke like a tiny violin.