Is it lawful for an employer to terminate an at-will employee for filing a harassment complaint?

QUESTION(S) PRESENTED (I). Is it lawful for an employer to intentionally terminate the employment of an “AT WILL” employee because he/she has filed or attempted to file a complaint of workplace harassment by a co-worker or supervisor because of his/her race, national origin, sex and/or sexual orientation (known or perceived)? (Il). Is it lawful for an employer to terminate the employment of an “AT WILL” employee for reason(s) its senior management/owner undoubtedly knows to be in large part made-up (a fabrication)? (II). Aside from the nocuous allegations that were discredited by the district court at trial in this case, is there any other factual evidences and/or statements on the record that proves my supervisor and/or T&M senior management/owner acted unlawfully? And if so, is that unlawful conduct(s) a violation of any federal antidiscrimination laws? (IV). Is it lawful for an employer who is engaged in a civil litigation in federal court against a former “At Will” employee (whether pro se or represented by counsel) to knowingly submit to the court false and/or misleadingly statements in the form of affidavits, memorandum of law and eyewitness statements (written and verbal)? (V). Is there a ruling or judgment by the lower courts in this case that can be reverse?