I would imagine the Warlord to be a manipulator of the battle field, throwing up walls of stone, causing earthquakes to daze/incapacitate waves of weaker creatures, enchanting himself with ancient magical artifacts to wade into battle armored by the earth perhaps?
Possible earth based/war spells
Turning the ground to quicksand beneath your enemy's feet.
Spewing lava from your hand to burn him
opening a crack in the earth that opponents can fall into
and so on....
as to how WAR is a school of magic
enchanting blades to be sharper or hit harder
spells that cause all dice rolled to ignore armor (be considered crits)
striking fear into your enemies
spells that cause opponents attacks to all be considered noncrits
spells that cause armor and weapons to shatter when striking him
lots of options here, but you may be right in that direct damage for the warlord at least will be accomplished best through creatures or attacks and less through spells.
again just my own imaginings.
