| Hint | Answer |
| Military colleague... | |
| Portrayed by... | |
| Military colleague... | |
| Portrayed by... | |
| Fought this plastic menace shortly after regenerating... | |
| Tried to negotiate peace with this underground race shortly after... | |
| Accidentally transports to a parallel Earth in this serial... | |
| Goes up against this nemesis throughout his second season... | |
| Portrayed by... | |
| Culminating in a fight with 'the Devil' in... | |
| Visited this planet twice, once in aide to the king, once to aid his now-adult daughter | |
| Is called by the Time Lords to help defeat this legend (with the help himself... twice)... | |
| Forced twice to go up against this race of half-wits who allied themselves with the Daleks | |
| Found this new, recurring, warrior-race foe in The Time Warrior | |
| Forced to regenerate due to... | |
| ...with the help of this fellow time-lord... | |