Claw and knckles photon arts?( Extra mode)

[Nayte]

Anyone know where to get the claw photon art? Ive been doing S ranks on missions with Tonnio in my party but doesnt give me one.
Im also wondering where/how to get the other knuckle photon arts. Again, i did S ranks with Nav in my party but still no luck. Maybe i should just keep trying?

[mechatra]

Just keep trying buddy. Oh and dont just do the same mission over and over. Switch it around sometimes.