From 1d4chan

Nuffle is a Chaos God of the alternate Warhammer Fantasy universe, Blood Bowl. His name is inspired as a pronunciation of "NFL", as in "National Football League" of American Gridiron Football.

Nuffle was an ancient Chaos deity who was entirely forgotten by the time of the Warhammer that is known. His ancient tomes and pamphlets, from another universe, were discovered in an ancient temple of his by greenskins and Dwarfs during a battle between the two factions.

The Dwarfs who attempted to decipher the texts went mad, but produced a legible playbook. Both armies abandoned the battle and instead resolved their differences with a game of Gridiron Football, a practice which quickly spread throughout the world.

The madness of Nuffle is absolute. All wars ended, races from greenskin to Vampire to Daemon abandoned all other goals than watching the games and playing in them. Nuffle's high cultists, Coaches, lead all beings in obedience to him. Nuffle imposes rules, but is not a true God of Law. He allows cheating, trickery, and destruction but is not a Ruinous Power.

The Four Chaos Gods themselves submit to his rule absolutely, and put aside the Great Game to focus on Nuffle's Big Game.

Nuffle only allows fortune, but his blessing is always bad luck. There is no known way to avoid his attentions, or to draw them. He has no Daemons or Champions, and creates no Chaos Spawn. See? He even lets you say the words!

The Chaos Gods of Warhammer 40,000 and Warhammer Fantasy
Four Main Chaos Gods: Khorne - Nurgle - Slaanesh - Tzeentch
Other Gods of Chaos: Archaon - Hashut - Horned Rat - Nuffle
Malal - Morghur - Necoho - Zuvassin
Chaos Gods of Law: Alluminas - Arianka - Solkan the Avenger