Lithuanian to English Law/Patents Law (general) atsiliepimas, ieškovas, ieškinys dėl žalos atlyginimo

Dear colleagues,

I need urgent help with a Lithuanian term "atsiliepimas į ieškovo [pavadinimas] ieškinį dėl žalos atlyginimo".
For the term "atsiliepimas" I ussually use "statement of defence", but this time there is a contradiction between two terms: "statement of defence" and "action for damages". I cannot find if there is a possibility to use the term "statement of defence to action for damages"? Or maybe it is possible to use: "response to action for damages"?
Also I want to ask what English word should be used for the term "ieškovas" in cases for action for damages.
Which term is the most suitable: "plaintiff", "claimant" or "applicant"?

Thanks a lot in advance.