From The Lion King. " Composed by Elton John (music) and Tim Rice (lyrics.)

Original voices:
(British) Scar: Jeremy Irons
Shenzi: Whoopi Goldberg
Banzai: Cheech Marin
Ed: Jim Cummings

Castilian voices:
Scar speaking: Ricard Solans
Scar singing: Jordi Doncos
Shenzi: Maria Dolores Gispert
Banzai: Antonio García Moral
Ed: Javier Pontón

I got no clue who is singing in Russian. If anyone knows, please tell me :)

Russian lyrics to English translation can be found here: http://lyricstranslate.com/fr/be-prepared-russian-be-prepared.html
French & English (Russian excluded) translations made by me.

Nice to know there is a Yandere Trio. Thanks for the ones who told me so. This song is perfect for them!

Pics credit: from Pixiv/Deviantart/Zerochan
America:
By 百瀬あん
「新入り？」by まりめ
hmhm page 1 by veus
By bwusagi
By bwusagi
By iAlly
By Okichi
囚人さん by かのう
Unknown artist
By Enoking
By 8t8s
＊ヘタリア＊ by さヲさん。＠ついったーはじめた

Russia:
By Shibue
By Sires Black
【ヘタリア】冬【おそろしあ】 by 樂
By HyLian-Of-Ooo (with the Baltic trio)
By t2r
▂▅▇█▓▒░(＾し＾)░▒▓█▇▅▂ by たけ＠自家通販中
By Ooshi
By Punpunichu
崩壊と by はづき
By Teen
By Fudeji
День рождения by 293
By Aiharasuke

Spain:
ヘタリアろぐづめ３ page 1 by 西峰かや
Unknown artist
Your kisses taste of rust by C-omrade
Unknown artist
Unknown artist
Unknown artist…
Unknown artist (all can be found on zerochan)
＃73 by とくこ
Unknown… again
Unknown artist
ほぼ兄さんログ２ page 4 by 甘噛
By Mametsuko
ついろぐ【APH腐】page 2 by とくこ