Anime with asexual (ace) and/or aromantic (aro) characters. Most are headcanons.
Manga version: https://myanimelist.net/stacks/29210
TV, 2018,
13 eps
Me:-
Author:8
Yuu Koito (demiromantic, demisexual/ace, and lesbian) (protagonist)
Touko Nanami (lithromantic and lesbian) (main)
Seiji Maki (aroace) (supporting)
TV, 2016,
120 eps
Me:-
Author:-
Kusuo Saiki (aroace) (protagonist)
TV, 2017,
12 eps
Me:-
Author:8
All gems (ace and pan) (main and supporting)
TV, 2017,
12 eps
Me:-
Author:-
Mito (aroace) (supporting)
TV, 2020,
12 eps
Me:-
Author:-
Shouko Tanimoto (aroace) (supporting)
TV, 2015,
24 eps
Me:-
Author:8
Makoto "Suna" Sunagawa (aroace) (main)
ONA, 2022,
12 eps
Me:-
Author:-
Anzu Hoshino (aro) (protagonist)
TV, 1999,
? eps
Me:-
Author:-
Monkey D. Luffy (aroace?) (protagonist)
TV, 2019,
24 eps
Me:-
Author:-
Senkuu (aroace) (protagonist)
TV, 2014,
12 eps
Me:-
Author:8
Umetarou Nozaki (aroace) (main)
TV, 2018,
13 eps
Me:-
Author:-
Mitsuyoshi Tada (aro?) (main)
TV, 2008,
13 eps
Me:-
Author:8
Takashi Natsume (aro?) (protagonist)
TV, 2005,
26 eps
Me:-
Author:8
Ginko (aro?) (protagonist)
TV, 2003,
13 eps
Me:-
Author:10
Kino (aro?) (protagonist)
TV, 2006,
37 eps
Me:-
Author:-
Light Yagami (aro?) (protagonist)
L Lawliet (aro?) (main)
TV, 2006,
25 eps
Me:-
Author:-
Lelouch Lamperouge (aro?) (protagonist)
Lloyd Asplund (aro?) (supporting)
TV, 2015,
24 eps
Me:-
Author:-
Souma Yukihira (ace?) (protagonist)
TV, 1998,
27 eps
Me:-
Author:-
Ryou Bakura (aroace?) (supporting)
TV, 2021,
20 eps
Me:-
Author:8
Fushi (ace?) (protagonist)
TV, 2017,
13 eps
Me:-
Author:6
Kobayashi (aro?) (protagonist)
TV, 1997,
276 eps
Me:-
Author:7
Satoshi/Ash Ketchum (aro?) (protagonist)
TV, 2017,
170 eps
Me:-
Author:-
Yuno (aro?) (main)
TV, 1986,
153 eps
Me:-
Author:-
Piccolo (aroace?) (supporting)
TV, 2012,
26 eps
Me:-
Author:-
Kars (aro?) (supporting)
TV, 2023,
24 eps
Me:-
Author:-
Maomao (aro?) (protagonist)
TV, 2014,
24 eps
Me:-
Author:-
Su-won (aro?) (supporting)
TV, 2004,
74 eps
Me:-
Author:8
Johan Liebert (aro?) (main)
Nina Fortner/Anna Liebert (aro?) (main)
TV, 2009,
11 eps
Me:-
Author:8
Akira "A-chan" Okudaira (ace/demisexual and lesbian) (main)
TV, 2003,
13 eps
Me:-
Author:2
Naozumi Sudo (aroace?) (supporting)
TV, 2013,
12 eps
Me:-
Author:7
Tomoki Kuroko (ace?) (supporting)
TV, 2013,
12 eps
Me:-
Author:-
Haruka "Haru" Nanase (aro?) (main)
TV, 2006,
14 eps
Me:-
Author:6
Yuki Nagato (aro?) (main)
TV, 2006,
26 eps
Me:-
Author:9
Haruhi Fujioka (demisexual and straight/NBLM) (protagonist)
TV, 2016,
12 eps
Me:-
Author:-
Tanaka (aro?) (protagonist)
TV, 2016,
12 eps
Me:-
Author:7
Sakamoto (aro?) (protagonist)
TV, 2010,
13 eps
Me:-
Author:7
Takatoshi Tsuda (ace?) (protagonist)
TV, 2015,
12 eps
Me:-
Author:7
Saitama (ace?) (protagonist)
TV, 2011,
13 eps
Me:-
Author:6
Shun Matsuoka (aroace?) (main)
TV, 2020,
12 eps
Me:-
Author:-
Catarina Claes (aroace?) (protagonist)
TV, 1999,
62 eps
Me:-
Author:-
Kurapika (aro?) (main)
TV, 2016,
22 eps
Me:-
Author:9
Rei Kiriyama (aro?) (protagonist)
TV, 2014,
12 eps
Me:-
Author:10
Sei "Seishuu" Handa (ace?) (protagonist)
Movie, 2006,
1 ep
Me:-
Author:7
Sawada (aroace?) (supporting)
TV, 2016,
13 eps
Me:-
Author:6
Mina "Pinky" Ashido (aro) (supporting)
TV, 2006,
12 eps
Me:-
Author:7
Balalaika (ace?) (supporting)
TV, 2012,
12 eps
Me:-
Author:-
Rikka Takanashi (ace/demisexual and straight?) (main)
ONA, 2018,
10 eps
Me:-
Author:7
Resasuke (aro?) (supporting)
TV, 2011,
60 eps
Me:-
Author:-
Tatsumi Oga (aroace?) (protagonist)
TV, 2011,
11 eps
Me:-
Author:8
Yoshino Takatsuki (aro?) (main)
TV, 2023,
28 eps
Me:-
Author:-
Frieren (aroace) (protagonist)