1 year before 15 arc
8 Years before Present

Dazai was the soul Witness to Mori killing the Port mafia boss.

Oldest to youngest

Very old - Fyodor
Very old - Bram

42 - Hirotsu
37 - fukuzawa
37 - Fukuchi
32 - Mori
24 - Francis
21 - Shibusawa
20 - Poe
20 - Kajii
20 - Lovecraft
19 - Nathaniel
19 - Arthur Rimbaud
19 - Oda
18 - Nikolai
18 - Ranpo
18 - Kouyou
17 - Ango
17 - Yosano
16 - Higuchi
14 - Mark
14 - Dazai
14 - Chuuya
14 - Kunikida
13 - John
12 - Margaret
12 - Akutagawa
11 - Tachihara
11 - Lucy
10 - Atsushi
10 - Tanizaki
10 - Gin
8 - Rokuzo
6 -Kyoka
6 -Kenji
5 - Q/Kyusaku
2 - Aya

Wasn't written yet - Sigma

?? - Agatha Christie
?? - Natsume
?? - Teruko
?? - Jouno
?? - Tetchou
?? - Ace
?? - paul valeraine