[tonio44]

Spoiler for chapter 130 spoiler:

The topless, dark haired sekirei is the number 44. It was written on her top before Kaho destroyed it.

We saw the 44 mark on her pullover in the beginning of chapter 123 (on page 5 or 6), just after Sanada found his jinki. She was in a group of sekirei and ashikabi who watched him an his sekirei.

It would seen that the Sanada's sekirei used their norito before fighting the other sekirei. I hope they named herself and numeroted herself !