I.F., also known as If (イフ Ifu) in the OCG, is an archetype made up of the various forms of "I.F.".
All members of this archetype are DARK Spellcaster monsters with 0 ATK and DEF. "I.F." shares a similar concept of "Yubel", which the very last of the "I.F." monsters can apply its effect whenever it battles. When a "I.F." monster is destroyed, the next evolution can be Special Summoned. Interestly, both "I.F." and "Yubel" evolutions also used German in their Japanese name.
|I.F./I.F. - Split Emotion||Yubel|
|I.F. - Grudgeful Presence||Yubel - Terror Incarnate|
|I.F. - Unforgettable Trauma||Yubel - The Ultimate Nightmare|
Similar to "Yubel" Deck, the "I.F." Deck revolves around destroying the main monster, "I.F.", to activate its effect and Summon its various forms; to either stall the game and/or inflict damage by forcing the opponent's monsters to attack them.