Ok, time to conjure up some lethality with this article. This is about to get really weird and anime-y. Buckle up kiddies, it's gonna be awesome!
First up is Hisoka, the main antagonist from the first arc of HunterxHunter. This guy is absolutely insane with bloodlust! That being said, he's also very strategic and calculating when it comes to combat. His "Bungee-Gum" is a force to be reckoned with, not to mention what he can do with a deck of playing cards (like decapitation). Overall he's a total badass who can't really get the job done. Hisoka would be the resident jack of all trades because of his wide range of abilities.
2. Lord English
Next up, let's go to a more or less obscure part of the internet. Second on the squad list is Lord English! Lord English is the antagonist toward the end of the webcomic Homestuck written by Andrew Hussie.He's a massive brute with dominion over time and essentially invincibility. Throughout his existence in the webcomic the protagonists are constantly trying to figure out how to take him down to no avail which is why he's on the squad. You can't beat him. You just can't. He's basically all powerful. Lord English would be the tank of the squad as well as the "berzerker" due to his invulnerability and stamina as well as short temper.
Third is a complete and total badass, Gotou. He's the main antagonist toward the end of Parasyte: The Maxim. Gotou is actually an amalgamation of 5 parasites controlled by Gotou (The main parasite). He can morph each limb of his body to suit his needs (including his head). He has enough agility and reflexes to dodge bullets, enough strength to throw vehicles around like toys, and even comes equipped with hyper regenerative powers. Gotou would be the scout/assassin for the squad due to his lethality, cunning, agility, and stealth.
4. Dio Brando
Last, but certainly not least, we have Dio Brando! Dio was the main protagonist through the first arc of JoJo's Bizarre Adventure. Dio is smart, manipulative, calculating, lethal, strong, immortal, and can turn anyone into a vampire by sucking out their life force thus turning them into his slave. Dio would be the tactician and leader or this particular Suicide Squad because of his capabilities as such.
There you have it ladies and gents'! My hand-picked Suicide Squad, and might I say it's nigh undefeatable!