It is reported of Sertorius, that he never slew any man in his anger, to satisfy his own private revenge, nor ever insulted over anyone whom he had overcome;
Plt Sertorius Chapter 5: Marius vs Sulla.

In straightforward fighting, no commander in his time was more bold and daring, and in whatever was to be performed in war by stratagem, secrecy, or surprise, if any strong place was to be secured, any pass to be gained speedily, for deceiving and overreaching an enemy, there was no man equal to him in subtlety and skill.
Plt Sertorius Chapter 10: Sertorius is invited by the Lusitanians

As soon as he heard of his mother's death, he had almost cast away himself and died for grief; for he lay seven days together continually in his tent, without giving the word, or being seen by the nearest of his friends
Plt Sertorius Chapter 22: Sertorius in Spain; complots.