Does English language recognise the term fouler as one who commits foul/s other than just an adjective like 'fouler deeds' etc?I have seen foul being used as a verb as in railways such as 'fouling area' where cars are allowed to derail etc.We also say that he fouled up the situation,but I have not heard persons calling someone a fouler.
We can generate one-who-does nouns (ending in -er) from verbs on an ad hoc basis. Watching a basketball game on TV with friends, say, we might be distracted for a moment when someone comes in the door to join the party, and upon returning, we see a player standing at the free-throw line. We could ask, Who was the fouler? although we'd probably say Who fouled him?
Dictionary.com doesn't supply 'fouler' as a word. That isn't to say that it is never used, as language does change, but I have never heard it used as a noun to describe a person in the way you are asking.
GloWbE has 20 matches for "fouler" as a noun; but half of them are wrongly classified. I count seven of them that are clearly nouns: six of these are derived from "foul" in the sporting sense. The seventh appears to be a bird-catcher, but evidently a quotation in archaic spelling. There are also two very similar quotes from New Zealand that I can't make much sense of, but they appear to be something in fashion: but they might be comparative adjectives used in a rather odd syntax.