I don't know on april 13....

April 13 Ryota Nango (Gizoku)
Hamel and Sizer (The Violinist of Hameln)
Aron Luke Walensa and Shun Makabe (Tokimeki Tonight)
Ataru Moroboshi (Urusei Yatsura)
Apple (Zillion)

I don't know any on my birthday: September 5.

now u do:
September 5 Haohmaru (Samurai Shodown/Samurai Spirits)
Manta Oyamada (Shaman King)
Mimu Emilton (Idol Project)
Megumi Mikihara (Tokimeki Memorial)
Suzumi Aogiri (Ayashi no Ceres)
Mariko Kouda (voice actor) Miki Koishikawa (Marmalade Boy), Miyuki (Miyuki-chan in Wonderland), Yuri (Dirty Pair Flash)

uhhh
 

umm idk.
minez may 21

My birthday is December 20. I don't think I've heard of any anime characters with my birthday. They always seem to be in the spring or in September.

May 21 Chichiri (Fushigi Yuugi)
Patricia McGlass (TokiMemo Pocket - Koutei no Photograph)
Asuka Tsukishiro ([Zettai Muteki] Raijin-Oh)
Masayo Kurata (voice actor) Dorisu (D4 Princess), Furea (Toki no Daichi)
Kaori Shimizu (voice actor) Reine (Serial Experiments lain), Boogie Pop, Touka Miyashita (Boogie Pop Phantom)

December 20 Polylina (Galaxy Fraulein Yuna)
Mamoru Izawa (Captain Tsubasa)
Sasami (Tenchi Muyo)
Sakuya (Sister Princess)
Yumi Touma (voice actor) Urd (Aa Megami-sama), Yui (Fushigi Yuugi), Deedlit (Lodoss), Hinako Ninomiya (Ranma 1/2), Cecily Fairchild (Gundam F-91)
Chisa Yokoyama (voice actor) Sasami (Tenchi Muyo), Chiaki Enno (Zenki), Sakura Shinguji (Sakura Taisen), Lucrezia Noin (Gundam W), Ryoko (Nadesico)

okay..march 20th?

i know its when the iraq war started in 2002. XD

March the 2nd (don't know any anime b-day yet :P)

Edit: found what anime characters lolz.

Sanji (one piece) And Holy Girl Iron Maiden Jeanne(shaman king)