Supreme Merits are primarily used to uncap characters. They are needed for the later stars on SR and SSR characters.
|Uncap SR to 5★||1|
|Uncap SSR to 4★||3|
|Uncap SSR to 5★||3|
|Upgrade Revenant Weapons (step 1)||10|
|Upgrade Revenant Weapons (step 3)||10|
|Upgrade Revenant Weapons (step 5)||10|
The most common way to get Supreme Merits is from Proto Bahamut. They drop occasionally, from flip chests, and most players will run it many times for Horn of Bahamut and Rusted Weapons. The only caveat is that you must be rank 50 to see Proto Bahamut raids, and they tend to only show up in the raid list rarely and fill up quickly. For players not yet rank 50, many events have Supreme Merits as a reward in some format. For Showdown events, they are available in the event shop. For Scenario events, they are usually in the honor collection rewards.