*pls reply - AS results gone sort of wrong

However, will universities HAVE to see my AS Biology grade? It feels really embarrassing since I’ve never gotten such a low grade.

Will this completely ruin my chances at getting an offer at the universities I’ve chosen? For additional info, my IGCSES were 2A*s and 6As.

Yes. As UCAS say here (with their own emphasis): "You must enter all your qualifications from secondary education onwards – whether you have the result (even any that were ungraded) or you’re still awaiting exams and results."
If you fail to mention a qualification, and the university finds out, they can withdraw any offer or place.
No. Some of the universities you mention explicitly state that that ignore AS grades (on the basis that many students won't have them, and will have done linear A levels, which don't include an AS level grade, so to use them would be unfair).
For example, Manchester say here that "AS-level results are not considered as part of the standard admissions process at the University. The exception to this is Medicine and Dentistry courses, where the School of Medical Science requires evidence of a broad programme of study."

Thank you very much for your response. It has given me some hope. I also see on King’s and Queen Mary’s website that they don’t consider AS results at any point of the process either. Just for clarity: if I were to drop Biology, and continue with History, Lit, Math and EPQ and *hopefully* achieve 2A*s and 2As or anything similar to this (and have good predicted grades), then my C in Biology will be completely irrelevant and won’t be the reason of any negative outcome, correct?

Well, I didn't say that your AS Biology grade "will be completely irrelevant and won’t be the reason of any negative outcome". You asked, "Will this completely ruin my chances at getting an offer at the universities I’ve chosen?" and I said "No", and then provided an explanation.
There's quite a gulf between "completely ruin my chances" and "completely irrelevant". I suspect that Oxford, and potentially the LSE (if you opt to apply there), will look at the grade and will not consider it irrelevant. However, I wouldn't go as far as saying that it would "completely ruin" your chances of an offer from those universities.

...can 3 very good A-Level grades and a very good EPQ grade overshadow an unsatisfactory AS grade?

Yes.

Hi everyone, so I received my Cambridge and Edexcel grades for my AS level and got the following: A for History, A for Literature, B for Math (however I’ve sent for a recheck since it was very close to an A) and a C for Biology.
Biology completely shocked me since I had gotten an A on the mocks and never gotten below an A on class tests and midterms. And I had worked incredibly hard. I’m still convinced that something has gone wrong with my grading and asked for a check (I was also very satisfied with how the exams went).
I am going to applying for Law soon at I have ambitious choices such as Oxford and King’s (and maybe even LSE but still debating). I have also chosen Manchester and Queen Mary. I am going to sit my LNAT soon and hopefully get a good score on that.
Now for my real question, I know that if I work really hard next year, I can get an A* for History and Literature and get an A for Math (I will drop Bio and do an EPQ instead which hopefully will be A*/A). However, will universities HAVE to see my AS Biology grade? It feels really embarrassing since I’ve never gotten such a low grade. Will this completely ruin my chances at getting an offer at the universities I’ve chosen? For additional info, my IGCSES were 2A*s and 6As.
Please give me any advice, I have been crying since yesterday about this.
UPDATE of REMARK: I went for priority marking so have gotten my Math grade and it’s gone up to an A! That’s good, still awaiting news on Biology.