Belt Colors and Mission Ranking ( ascending order ):
| Belt | Rank |
|---|
| White | E |
| Purple | |
| Red | D |
| Yellow | C |
| Green | B |
| Blue | A |
| Brown | |
| Black | S |
| X |
| Keres | |
A mission will be given a rank, let say C-rank and the assigned ninjas will be picked from available resources that meet the belt requirements or higher, in the case for C-rank, Yellow belt or higher.
However, this is a general rule and not a hard rule. Mission items can be re-configured according to the situations i.e. it is flexible and agile.
This was explained in Chapter 7 during the Esyl escort mission debrief session before the nearby village mysterious sickness support mission started.
On that note, I wonder why
Hailey assigned 2 Red belt Team Leaders and 3 Purple belt ninjas to a D-rank mission that can potentially become a B-rank mission

.
So that Zycris character growth will be more prominent than before if it was not noticeable before?
P/S: This list is incomplete and un-certified. It could be missing some belt colors and mission ranks.