Chaos;Head カオスヘッド (Kaosu Heddo)

Alternative Name: 混沌之脑 (Hùn Dùn Zhī Nǎo)

Genre: Action, Horror, Drama, Romance, Mystery, Psychological, 
               Sci-Fi, Supernatural, Harem, NEET, Otaku, Thriller

Description: 

Takumi Nishijō suffers from intense delusions as a result of his apparent schizophrenia and the extremely secluded lifestyle he lives as a hikkikomori. One day he accidentally stumbles upon a gruesome murder scene, a part of a chain of events called "New Generation". After this, his life gets caught up in these events, and he meets a bunch of increasingly insane anime girls with swords.

Episode
Season 1: 12 Episodes
Season 2: 12 Episodes + 1 Special + 1 Movie

Original Run
Season 1: October 9, 2008 – December 25, 2008
Season 2: January 11, 2017 – March 29, 2017
Movie: June 17, 2017

Studio: Madhouse (S1) / SILVER LINK. (S2)

ChäoS;Child

Alternative Name: 混沌之子 (Hùn Dùn Zhī Zǐ)

Description: 

Six years following the events of Chaos:Head, a new string of deaths similar to the New-Gen murders have started up in the newly rebuilt Shibuya area. These incidents have taken the attention of a Highschooler: Takuru Miyashiro, and the newspaper club. Investigating the incidents of the present as well as their connection to the events of the New-Gen Crimes Takuru and his friends find themselves being pulled deeper into the incidents than they ever believed possible.

List of Songs (directly to CrimNight Muse Garden)

1. F.D.D                                                [Opening]

2. Super Special                                [Ending]

Choas; Head Vocal Collection
1. Desire Blue Sky
2. Cry
3. Zaika ni Keiyaku no Chi wo
4. Gladiale 
5. Haritsuke no Misa                                             [Insert 3]
6. Harukanaru Idei Yona                                      [Insert 3]
7. Fake Me
8. A Will
9. Hallelujah no Fukuin 
10. Flag Tateyou yo
11. Mikkyou no Kubikazari
12. Fetishism Ark
13. Innoncence 
14. Synchro-shiyou yo
15. Kimi eno Tobikiri Quenka
16. Inori no Violet
17. Kono Sora no Kanata ni
18. Hateshinai Soukuu e
19. Hisui no Caviliere
20. Trust in Me
21. Love Power
22. Kokoro no Yami wo Kirisaite
23. Chiisana Koe ni Kidzuite
24. WHITE LILY
25. Calling
26. FORTUNE LOVE Night

Season 2:
1. Uncontrollable                     [Opening]
2. Chaos Syndrome                   [Ending]

Special:
1. Find the Blue                       [Ending]

Movie: 
1. Silent Wind Bell                   [Ending]

Real Boot Modulation -CHAOS;CHILD OST-

1. Hijitsuzai Seishounen

2. Gesshoku no Vanitas

3. Singularity

Manga 

1. Chaos; Head

Published:  May 21, 2008 – May 21, 2009
Volume: 1

2. Chaos; Head ~Blue Complex~

Published:  August 26, 2008 – August 27, 2009
Volume: 2

3. Chaos; Head H

Published:  September 26, 2008 – August 27, 2009
Volume: 1

4. Chaos; Child
Published:  December 29, 2015 – February 28, 2018
Volume: 4

5. Chaos; Child: Children's Collapse
Published:  August 26, 2016 – November 28, 2018
Volume: 3

Light Novel: ChäoS;Child: Children's Revive

Published: March 31, 2017

Volume: 1

Here is the preview:

Season 2: