In this quote from Livy (6.8.6):
"ita quocumque se intulisset victoriam secum haud dubiam trahebat."
"thus, in whatever direction he went, he carried certain victory with him."
The reflexive pronoun, "se", is deployed with, "secum"; a bizarre translation: "he carried himself (accusative, "se") certain victory with him ("secum")"; or, "wherever he advanced himself ("se trahebat"), he carried...", is better but doesn't sound right: does a general advance himself or lead his army?
The use of "se" works if it means, "he". This happens in indirect speech (accusative-infinitive) when the subject of an indirect statement is the same as the subject of the main verb; then, a reflexive pronoun must be used, in the accusative:
"rex dicebat se hostes superaturum esse."
"The king said that he ("se"; the king) would overcome the enemy." (Oulton, Book III, p.41).
Livy did not use an accusative-infinitive construction and "he" is already included in the two third-person verbs: "intulisset" & "trahebat".
What is the role of "se", here; what if it was omitted?