Yamamoto Sekai was born on February 21, 1991 in Kanagawa Prefecture, Japan.
Yamamoto started learning dance at age 2 as his mother ran a dance school. From fourth grade of elementary school to the first year of junior high school, he played the role of Young Simba in the musical The Lion King of the theatrical company Shiki Theatre Company.
In 2010, he was at the top 4 of the dance event STEP YA GAME UP 2010, held in New York. In 2012, he won the 2012 edition of the event in the hip-hop section.
In 2013, he auditioned to the EXILE PERFORMER BATTLE AUDITION.
On July 4, 2019, he got injured during the first concert of BATTLE OF TOKYO ~ENTER THE Jr.EXILE~ and was later diagnosed with metatarsal bone fracture, being absent from the July 5 to 7 concerts. He participated as MC only on the July 6 concert.
- Live Concerts
-  Miriam Yeung World Tour Live Hong Kong "Ladies&Gentlemen"
-  Miura Daichi - "DAICHI MIURA LIVE TOUR 2011 ~Synesthesia~"
-  Ketsumeishi "Aretsu? Kono Ojisantachi Mitakotoaru! Soudesu! Shita no Hou de Fes 2011 Tettere♪"
-  Ketsumeishi "Yami Kara Hikari e Nyoui Doun! Ketsumeishi Tsua 2013 ~etsu? Tsuika Kouen? Itsu Yaru no? …Imadesho!"
- Music Video Appearances
-  Shimizu Shota - "Madaowaranai"
-  Miura Daichi - "SHOUT IT -LIVE EDITION-"
-  EXILE SHOKICHI - "IGNITION"
-  GENERATIONS - "AGEHA"
- Main article: Sekai/Gallery
Oldest Member of FANTASTICS
|Gallery | Category | Songs navbox|
|Members||Sekai (L) | Sato Taiki (L) | Sawamoto Natsuki | Seguchi Leiya | Hori Natsuki | Kimura Keito | Yagi Yusei | Nakajima Sota|
|Honorary Members||Nakao Shota|
|Albums||1. FANTASTIC 9|
|Other Albums||BATTLE OF TOKYO ~ENTER THE Jr.EXILE~|
|Singles||1. OVER DRIVE | 2. Flying Fish | 3. Dear Destiny | 4. Time Camera | 5. Hey, darlin' | 6. Winding Road ~Mirai e~ | 7. High Fever|
|Concerts & Tours|
|Tours||1. FANTASTIC NINE | |
|Concerts Featured In||EXILE: STAR OF WISH|
GENERATIONS: SPEEDSTER | MAD CYCLONE
Other: BATTLE OF TOKYO ~ENTER THE Jr.EXILE~ | LDH PERFECT YEAR 2020 COUNTDOWN LIVE 2019▶︎2020 "RISING"
|Units & Other Acts|
|Associated Acts||EXILE TRIBE | Jr.EXILE|