What defence does presiding officer have against revengeful complaint?

First of all, it must be noted that nothing is an offence which is done by judicial officer in good faith while discharging  his official duty. In this regard, would like to draw your attention towards Section 197 of Criminal Procedure Code which is reproduced here under:

197. Prosecution of Judges and public servants.

(1) When any person who is or was a Judge or Magistrate or a public servant not removable from his office save by or with the sanction of the Government is accused of any offence alleged to have been committed by him while acting or purporting to act in the discharge of his official duty, no Court shall take cognizance of such offence except with the previous sanction-

(a) in the case of a person who is employed or, as the case may be, was at the time of commission of the alleged offence employed, in connection with the affairs of the Union, of the Central Government;

(b) in the case of a person who is employed or, as the case may be, was at the time of commission of the alleged offence employed, in connection with the affairs of a State, of the State Government: 1 Provided that where the alleged offence was committed by a person referred to in clause (b) during the period while a Proclamation issued under clause (1) of article 356 of the Constitution was in force in a State, clause (b) will apply as if for the expression" State Government" occurring therein, the expression" Central Government" were substituted.

(2) No Court shall take cognizance of any offence alleged to have been committed by any member of the Armed Forces of the Union while acting or purporting to act in the discharge of his official duty, except with the previous sanction of the Central Government.

(3) The State Government may, by notification, direct that the provisions of sub- section (2) shall apply to such class or category of the members of the Forces charged with the maintenance of public order as may be specified therein, wherever they may be serving, and thereupon the provisions of that sub- section will apply as if for the expression" Central Government" occurring therein, the expression" State Government" were substituted.

(3A) 1 Notwithstanding anything contained in sub- section (3), no court shall take cognizance of any offence, alleged to have been committed by any member of the Forces charged with the maintenance of public order in a State while acting or purporting to act in the discharge of his official duty during the period while a Proclamation issued under clause (1) of article 356 of the Constitution was in force therein, except with the previous sanction of the Central Government.

(3B) Notwithstanding anything to the contrary contained in this Code or any other law, it is hereby declared that any sanction accorded by the State Government or any cognizance taken by a court upon such sanction, during the period commencing on the 20th day of August, 1991 and ending with the date immediately preceding the date on which the Code of Criminal Procedure (Amendment) Act, 1991 , receives the assent of the President, with respect to an offence alleged to have been committed during the period while a Proclamation issued under clause (1) of article 356 of the Constitution was in force in the State, shall be invalid and it shall be competent for the Central Government in such matter to accord sanction and for the court to take cognizance thereon.

(4) The Central Government or the State Government, as the case may be, may determine the person by whom, the manner in which, and the offence or offences for which, the prosecution of such Judge, Magistrate or public servant is to be conducted, and may specify the Court before which the trial is to be held.

In addition to this, presiding official is protected under The Judicial Officers’ Protection Act, 1850. Sec. 1 of the 1850 Act,

as per  “Sec. 1--- Non liability to suit of officers acting judicially, for official acts done in good faith, and of officers executing warrants and orders—No Judge, Magistrate, Justice of the Peace, Collector or other person acting judicially shall be liable to be sued in any Civil Court for any act done or ordered to be done by him in the discharge of his judicial duty, whether or not within the limits of his jurisdiction : Provided that he at the time in good faith, believed himself to have jurisdiction to do or order the act complained of; and no officer of any Court or other person, bound to execute the lawful warrants or orders of any such Judge, Magistrate, Justice of Peace, Collector or other person acting judicially shall be liable to be sued in any Civil Court, for the execution of any warrant or order, which he would be bound to execute, if within the jurisdiction of the person issuing the same.

Further, there are various judicial pronouncements wherein courts have observed that that a person can't be prosecuted for an act done in good faith while discharging quasi judicial function. "Such a course, if permitted, would shake the confidence of authorities exercising judicial and quasi judicial functions, and expose them to unwarranted criminal actions,"

In view of aforesaid, presiding officer will be protected.

With respect to your second query regarding defence, it is to be noted that without knowing the contents of complaint it would be difficult to draft the contents of a reply to the complaint. Therefore more details are required to assist you in drafting a proper reply.