Aliasing fourth_doctor → 4th_doctor
Link to alias

Reason:

Suggest Doctor Who incarnations tags be style 4th_doctor
instead of fourth_doctor (4th being easier to spell).

example: I noticed misspelled tag eigth_doctor (now empty).

e621 *_doctor incarnation tag (of Doctor Who):

3 first_doctor . . . character

3 second_doctor . . . character

3 third_doctor . . . character

2 4th_doctor . . . character
5 fourth_doctor . . . character

3 fifth_doctor . . . character

3 sixth_doctor . . . character

3 seventh_doctor . . . character

1 8th_doctor . . . character
3 eighth_doctor . . . character

3 ninth_doctor . . . character

3 10th_doctor . . . character
10 tenth_doctor . . . character

13 eleventh_doctor . . . character

2 13th_doctor . . . character

* * *

So suggest aliases of:
1) first_doctor -> 1st_doctor
2) second_doctor -> 2nd_doctor
3) third_doctor -> 3rd_doctor
4) fourth_doctor -> 4th_doctor
5) fifth_doctor -> 5th_doctor
6) sixth_doctor -> 6th_doctor
7) seventh_doctor -> 7th_doctor
8) eighth_doctor -> 8th_doctor
9) ninth_doctor -> 9th_doctor
10) tenth_doctor -> 10th_doctor
11) eleventh_doctor -> 11th_doctor
12) Twelfth_Doctor -> 12th_doctor (none uploaded to e621 yet?)
13) Thirteenth_Doctor -> 13th_doctor

EDIT: The tag alias fourth_doctor -> 4th_doctor (forum #271619) has been rejected by @NotMeNotYou.

-1 to all. In common parlance when referring to the various incarnations of the Doctor, the ordinal form of each incarnation's name is fully spelled out. (See https://en.wikipedia.org/wiki/The_Doctor_(Doctor_Who)#Actors .) If anything, the reverse should be used instead. (Alias 4th_doctor to fourth_doctor, 1st_doctor to first_doctor, etc.)

The tag alias fourth_doctor -> 4th_doctor (forum #271619) has been rejected by @NotMeNotYou.