Greek gamma, through Etruscan.
C
for centuries C spelled both [k] and [g] in Latin, which is why the name Gaius was abbreviated as C. The Romans lived with one letter for two sounds until somebody fixed it.
Archer · Becker · Bianchi · Black · Cameron · Campbell · Carpenter · Carroll · Carter · Casey · Castillo · Chambers · Chandler · Chapman
In the modern alphabet this letter is number 3 of 26. Before it comes B, after it D. The order itself is inherited: Latin took it from Greek, Greek from Phoenician, and the sequence has survived largely unchanged for about three thousand years. Every rearrangement since has been an insertion, not a reshuffle.
This is a consonant: it sets the hardness of a name and how it meets the next word. In a corpus of 315 surnames this letter opens 26 and closes 0. Among the 96 given names in the base it appears in 25. The surname carrying the most of it is Ricci, with 2.
Michael · Richard · Charles · Christopher · Jacob · Nicholas · Eric · Patrick · Jack · Lucas · Grace · Jessica
These letters came from the Greek alphabet.