Bab 1405: Superior To The Soul Sphere.

They already have power at the limit of the light side of the void universe. So they can do something they have wanted to do since they met the realm lord in the Gattling plane. 

They said at the same time, "The first thing we must do is remove the system from monitoring us."

The two of them have synchronized thoughts now that their existence has fused completely. Legion-5 was already part of Legion-7 when they performed the second stage of unity but now their souls have completely become one. 

There's no boundary between their souls anymore so their thoughts are aligned. They should be one entity if not for their shard of power anchoring their consciousness separately. 

Synchronized thought is a side effect of unity. It is not the synchronization of memory that they had as clones. They used to have different thoughts in the past but now their thoughts align because they have the same spark of consciousness of Legion-7.