The Secret Plan.

The Tenth clone replied, "I am the secret weapon you have prepared, silly. You had me hide so that others wouldn't know about me."

Legion-1 remembered it now that it had been pointed out. Memories of their actions to create a secret clone to combat the exposure of their secrets and how they had purged the memories of those actions from their minds all returned to Legion.

They were suddenly enlightened. Legion-5 said to Legion-1, "Truly good thinking on your part."

The tenth clone also complimented him, "You always prepared for the worst. That's why we will achieve great things."

Every clone relaxed and also complimented Legion-1 for being smart when he created a secret clone when he created the others. But Legion-1 didn't reply. Instead, his eyes remained narrowed in suspicion. 

Maybe it was because he was in charge of their Origin, but he felt resistance towards this person. He can't explain why, he only knows that there are two contrasting facts.