Familiar Potentials

how often does it rank up? just keep collecting the same cards until it turns legendary or gotta use those cube things? lol sorry I just got back a few weeks ago

You can rank up to unique by fusing familiars together, but Legendary requires the cube things (Red Familiar Card) from the cash shop. I have no clue what the tier rates are like on the cubes.

You can attempt to rank up a familiar epic or lower by doing the following:
1. Level it up to 5 (by hunting monsters near your level with the familiar equipped and out)
2. Getting the required amount of rank-up points by fusing identical familiars (or using a fauxmiliar)

You need 50 Rank-Up Points to try to rank up Common-> Rare, and there's a 100% chance of succeeding.
You need 100 Rank-Up Points to try to rank up Rare -> Epic, and there's a 80% chance of succeeding.
You need 150 Rank-Up Points to try to rank up Epic -> Unique, and there's a 40% chance of succeeding.

If you fail the rank up, you lose half your rank up points.

You can get:
1 Rank-Up Point per Common Familiar
2 Rank-Up Points per Rare Familiar
3 Rank-Up Points per Epic Familiar
4 Rank-Up Points per Unique Familiar
5 Rank-Up Points per Legendary Familiar
15 Rank-Up Points per Suspicious Fauxmiliar
30 Rank-Up Points per Fauxmiliar

It's probably a bad idea to waste unique and legendary familiars to use as rank-up points. Fauxmiliars are wild cards that you can fuse into any familiar for points (so for familiars you only have one of), Suspicious Fauxmiliars come from the Familiar shop for 5k Familiar Points (once a week), or from the cash shop booster packs. They only mentioned regular (non-Suspicious) Fauxmilars in the original revamp notes as coming from booster packs, but it wasn't listed in the rates for booster packs on the website, and they haven't brought them up again in the new update notes, so I'm guessing they're probably just unobtainable for now.

In JMS, monsters only seem to drop Common and Rare ranked familiars (if Epic or higher drop, they're insanely rare, I can't find any info regarding people finding them post revamp), I think it's probably the same for us. So, for ranking up to Unique, Common and Rare familiars will probably be what you use for rank up points.