As a general rule any person may sue any other person for any actual or alleged wrong. If you are sued you will have two choices: (1) you may ignore the complaint, in which case there will be judgement entered against you by default, or (2) you may defend against the complaint, in which case you will incur legal fees and court costs (hint: good lawyers charge more per hour than many of us ever earned per week, and they don't want to turn off the faucet until the cistern is dry).

Nothing needs to be proven in order to file a lawsuit, only allegations must be made. In a criminal case the standards are innocent until proven guilty, and beyond a reasonable doubt. In a civil case (lawsuit) the standards are preponderance of the evidence, and guilty until proven innocent.

You may purchase liability insurance coverage to protect yourself against such claims. In the final analysis this not only does not stop lawsuits, it may encourage a lawsuit (plaintiff learns that there is an insurance company on the hook). Attorneys retained by your insurer will be primarily concerned with protecting the insurer; protecting you will be a secondary (although closely associated) priority. When the insurance company's bean counters see a claim, they will start estimating how much it might cost to defend that claim, and the initial response might well be an offer to settle for "nuisance value" (less than projected legal fees and court costs). Plaintiffs' lawyers understand this very well, and will pursue any case, under any fact situation, just for a quick payday on "nuisance value".

As far as being arrested goes, an arrest requires a showing of probable cause, i.e.: knowledge of facts and circumstances that would cause a reasonable man to believe that a crime has been committed, and a particular individual committed that crime. You may (probably will) be detained and questioned, perhaps repeatedly. Best advice I can offer is to simply state "I was in fear for my life and I was forced to defend myself. I have nothing more to say until I am represented by an attorney".

Once you have invoked the right to legal counsel nothing else can be done that can possibly result in admissible evidence. SHUT UP, LAWYER UP, MAX OUT THE CREDIT CARDS AND PAY THE RETAINER, AND LET YOUR LAWYER DO ALL OF YOUR TALKING FOR YOU. You are under no obligation to assist the state in building a case against you. Do not sit there like a dunce and let investigators and prosecutors question you over and over again, perhaps for hours, going over every detail, while you get tired and your memory slips a bit on sequence of events, words spoken, etc, etc, etc; all that will result is reports that show inconsistencies in your statements, which will not look good for you at the court house.

A final bit of advice: Don't wait until you need a lawyer to find one. Most reputable lawyers will allow you a brief consultation to discuss possibilities of representation without fee, or at minimal cost. Find a lawyer whose experience includes self-defense issues, one that you trust, and keep his number on speed-dial. Then, in addition to "I WAS IN FEAR FOR MY LIFE AND I WAS FORCED TO DEFEND MYSELF" you can add "I HAVE CALLED MY ATTORNEY AND I AM WAITING FOR HIS RESPONSE BEFORE I HAVE ANYTHING FURTHER TO SAY".

Don't get your dental work done at an auto body shop. Don't get your legal advice from a sales clerk at a gun store. Don't rely on internet forums for the best in criminal or civil law advice.