Thanks Recette for the answer, can't plus rep yet though @.@ I have to spread some more reps around. But I have this problem:
I do Boss quite often and I have Electro and Tesla (I could possibly get Thunderbolt) to partner with the Shard. It's just Chaos Tower 5th Boss is kind of long to kill and the 6th one is sort of impossible for me. Plus I don't have a Spicy Dragon seal (x.x)
I have another option though, I could switch to Water/Elec (I have a few spare authorities). So what could be a better option, lose Fire for my own Shard, or just rely on the Shard of the guardian?