BUR #4178 has been approved by @evazion.
create alias danganronpa -> danganronpa_(series)
create alias danganronpa_1 -> danganronpa:_trigger_happy_havoc
create alias super_danganronpa_2 -> danganronpa_2:_goodbye_despair
create alias new_danganronpa_v3 -> danganronpa_v3:_killing_harmony
create alias zettai_zetsubou_shoujo -> danganronpa_another_episode:_ultra_despair_girls
create alias danganronpa_3 -> danganronpa_3_(anime)
rename togami_byakuya_(super_danganronpa_2) -> togami_byakuya_(danganronpa_2)
The tags for the Danganronpa copyrights are currently a mess, both for users trying to find the base tags for games and for consistency in general. Changing them to English localizations will improve both of these areas.
Here is the current list of active Danganronpa copyright tags (that I was able to find):
danganronpa (series tag)
danganronpa_1 (main game 1)
super_danganronpa_2 (main game 2)
new_danganronpa_v3 (main game 3)
zettai_zetsubou_shoujo (spinoff known in English as Danganronpa Another Episode: Ultra Despair Girls)
danganronpa_3 (anime; very little relation to the third game)
danganronpa_gaiden:_killer_killer (anime spinoff)
danganronpa/zero (light novel prequel to Danganronpa Gaiden: Killer Killer)
danganronpa_togami (light novel focusing on Togami Byakuya)
danganronpa_another (Korean fangame)
super_danganronpa_another_2 (Korean fangame sequel)
Some of these tags are the Japanese titles, such as super_danganronpa_2 and new_danganronpa_v3 but there is also danganronpa_1, which is neither the English nor the Japanese official title, and zettai_zetsubou_shoujo, which is only half of the actual Japanese title. Additionally, the main series tag is just danganronpa which, due to its lack of a _(series) qualifier, could be referring to the first game or the series as a whole. In terms of ease of use, the Japanese names are an especially poor choice as only the first game actually begins with "Danganronpa" and most English-speaking fans have no idea the other games start with "super" and "new".
The worst part about the current tags is easily the tag for the anime, danganronpa_3. To any normal person, a reasonable assumption to make would be "danganronpa_1 is for the first game, so danganronpa_3 must be for the third game". This one isn't really Danbooru's fault so much as Spike Chunsoft's, however, because the third game is titled Danganronpa V3 and the anime is titled Danganronpa 3 (good job SC, really nice work). In any case, we need a better solution.
My proposal is to turn danganronpa_3 into a disambiguation wiki (by aliasing and then unaliasing it) and change the anime's tag to danganronpa_3_(anime). I considered danganronpa_3:_the_end_of_hope's_peak_high_school, but it still suffers the same issue in that it follows the format of the previous games' tags. As such, to the uninformed, it could well be the name for the third game. I think because of the confusion factor we can forego the full title for the anime and just use danganronpa_3_(anime) instead.