Titus Lartius may be an important Roman general, but Shakespeare doesn't seem super interested in him. His most important function seems to be delivering a big speech about how Coriolanus is such an awesome warrior. Check it out:
O noble fellow!
Who sensibly outdares his senseless sword,
And, when it bows, stands up. Thou art left, MARTIUS:
Thou wast a soldier
Even to Cato's wish, not fierce and terrible
Only in strokes;, but with thy grim looks and
The thunder-like percussion of thy sounds,
Thou madst thine enemies shake, as if the world
Were feverous and did tremble. (1.4.53-61)
Okay. We get it. Coriolanus is one bad dude. What's interesting is that Lartius talks about Coriolanus as if the guy is some kind of inhuman war machine whose sole purpose in life is to terrorize Rome's enemies. Why does this matter? Because the patricians are always talking about Coriolanus this way. They don't suck up to Coriolanus because they like him and think he's a good friend--they just use him to intimidate their rivals.