I think it was mentioned that Skullheart is SR.
Fullcloth would be SS, as there would be no other rank it would fit into. And I doubt Netmarble will make an SR as key, so...
X1 is the key unit for Fullcloth.
Good thing I kept that ZZ that I used for AS S. Now I just gotta get another A Zeta...
Game Count: 3200 Win Percentage: 65.81% Ranking: #15