so sometimes MF need to remove their armor every now and then as to streched out. Hitsu here been in his armor for more then few weeks which the limit for an MF is 5 weeks which their cells in his skin will stiffen over time.

Also Hitsu colour is different from his armor skin. Unlike other mf, Hitsu armor is design to withstand the cold depth of the armor and also the depth pressure.
Fun drawing him in a little darkish greenish blue colour XD