X-Naut PhDs are the scientists of Grodus' empire. They are the ones who create the various potions for X-Nauts and Elite X-Nauts that increase their power or health. They also created the Yux species and the
Magnus Von Grapple
. X-Naut PhDs themselves are a tough opponent since the potions they throw can set Mario on fire, increase their power, or heal themselves.
| The X-Naut Army | |
| Leaders: | | |
|---|---|
| Underlings: | X-Naut | | |
| Yuxes: | Yux | Mini-Yux | Z-Yux | | X-Yux | |
| Other: | Characters: | | | Beldam | Marilyn | Vivian | Doopliss |
| Groups: | |