The general consensus with Tormod is that his availability, for some reason, sucks in both games. Begnion's political strife is introduced relatively late into Path of Radiance; and Tormod joins the party in Radiant Dawn for the very beginning, only to vanish until the very end at the same level he was when he left, which is offensively low by endgame. Due to the presence of other mages with more solid magic growths, Tormod is more likely to be benched for the amount of bonus EXP and time that must be pumped into his growth. On the flipside, his unique skill, Celerity, earns him bonus points as the only mage in the first game to be able to move the same distance as mounted units, which apparently holds in the narrative itself. ("Who do you think taught him how to run?" — Muarim)
This section is depressing.
That aside, his few appearances are important to his character in that both of his entrances within Radiant Dawn's story are deliberate. Tormod appears in the first part at the behest of Sothe, charging in with reckless abandon and screaming the latter's name at the top of his lungs. He leaves at the conclusion of this arc to return near the end of the last part, where he fights under bleak circumstances until Ike recruits him. In either instance, he offers his aid to his longtime comrades in a heartbeat, eager to be of help and to protect what's important to them while asking nothing in return.