Very old gag. The "assistant" is actually the boss. Even happens accidentally, when a leader is covering a subordinate's position for some reason.
The Galactic Navy Officer Becomes an Adventurer
by Takuma Tomomasa , A_Itoh
Available on mangabuddy for reading, and for sale at https://www.amazon.com/dp/B0BT6V7CMM
by Takuma Tomomasa , A_Itoh
Available on mangabuddy for reading, and for sale at https://www.amazon.com/dp/B0BT6V7CMM