I thought Emerald and Ruby weapons were pain in the ass optional bosses, specificly if you dont have the underwater materia. Emerald Weapon just took along time, but there were tricks to get around him (9999 hp, 3 materia equiped, Aire Tam, 3,333 damage to everyone, 7,777=Lucky 7's).
Ruby was just a pain in the ass...even with level 90+ characters...