Ultor
"The avenger," a surname of Mars, to whom Augustus built a temple at Rome in the forum, after taking vengeance upon the murderers of his great-uncle, Julius Caesar. (Sueton. Aug. 21, 29, Calig. 24 ; Ov. Fast. v. 577.)
From Smith's Dictionary of Greek and Roman Biography and MythologyFrom Fasti By Ovid
Book V: May 12 Augustus dedicated a temple to Mars the Avenger (Ultor) August 1st, 2 BC on his avenging Julius Caesar's death, and another temple in 20 BC commemorating the recovery of the Parthian standards.
