Why is the noun plural after you are done signaling that there are no cats? "There are no cats here"

There is no cat here. - Singular
There are no cats here. - Plural

The verb "be" , an auxillary verb, is used as there is no full verb in the sentence. It takes a singular or plural form depending on whether you refer to one cat or many. The noun "cat" must be in agreement with the verb so it takes the plural "-s" to indicate a plural form of the verb or no "-s" if it remains singular. I can't see how this is confusing for you if you are a native speaker, if you are a learner of English please give me another example of the confusion so I can help further.