It is believed that all dragonborns are born to fight because they have the physical attributes that makes them the perfect warrior.
They are tall and strongly built, often standing close to 6½ feet in height and weighing 300 pounds or more. Their hands and feet are strong, talonlike claws with three fingers and a thumb on each hand. (Player's Handbook, pg. 35)
Dragonborns are a race that is tempered by war. It has always been a way of life for them. It was war that brought them together to the height of their civilization and it was war that brought the downfall of the mightiest empires the world has ever seen. The military traditions of the dragonborns started during the early days when they were just fragmented clans before the unification, serving in the conflict between Tiamat and Bahamut.
These unified clans had military discipline in common, which was a trait needed in ongoing war or for mere defense in the elder world. (Ecology of the Dragonborn, Dragon #365)
When the dragonborns finally unified into the Arkhosia empire. they became an unstoppable force that would finally find their match in the tieflings and devils of Bael Tunrath which would ultimately lead both empires to their doom. Even so, the dragonborn have nothing but utmost respect to the tieflings that they deem as worthy adversaries.
Although the glorious days of the dragonborns are now but a legacy and distant memory of their mighty heritage, dragonborns have retained their militaristic reputation and are respected as skilled fighters and inspiring warlords. There are two defining features that makes them a natural warrior; self-improvement and honor.
Dragonborn In Times of War
Dragonborns have always been in war throughout their history except during the peaceful days of the Arkhosia empire but even that was short lived when they met the Bael Turath empire. Most dragonborn feel that it is their obligatory duty to serve in the army. It is not only an honor to be able to serve in the battlefield but it is also a great opportunity to improve one's skill or to show them off.
A dragonborn is never conscripted. Each and every one of them gladly submit themselves into the service of an army with the willingness to fight. This not only happen to individual dragonborns but also to the society. When the time of war comes, every class of dragonborn society knows very well how to play their part in contributing to the war effort and to do so is a great honor.
A dragonborn weaponsmith aims to be the best, to push the boundaries of his craft, to sell weapons in a scrupulous manner, and to honor those who use his armaments by creating implements of worth. The dragonborn soldier, in turn, honors armorer, commander, and clan, by performing his or her duties well. He or she does
so by taking initiative in training and on the battlefield, and by helping comrades. Failing to recognize such interconnectivity is a failing of character. (Ecology of the Dragonborn, Dragon #365)
The passionate and sometimes obsessional drive of dragonborns to self improvement makes them take their training seriously. They train to perfect their skills with a weapon not only to satisfy their sense of duty but also to call themselves worthy of a proud military heritage. A well trained dragonborn soldier is one of the finest military examples that very few racial armies can emulate in terms of bravery, loyalty and discipline.
Dragonborns do not segregate between genders for joining the army. A male dragonborn warrior would call a female dragonborn his comrade-in-arms as readily as they learn to swing a sword and the opportunities for dragonborns to rise among the ranks are equal among genders.
The lowest rank in the dragonborn military is the Soldier (Monster Manual, pg 86) organized into groups led by a Commandant (Ecology of the Dragonborn, Dragon #365). Raiders (Monster Manual, pg 86) act more like light troops than scouts since the dragonborn physique is not ideal for stealth missions while Gladiators (Monster Manual, pg 86) act as frontline shock troops. The strongest of the dragonborn warriors are called Champions (Monster Manual, pg 87) and they often take the higher positions in the chain of command.
Dragonborn Elementalist (Ecology of the Dragonborn, Dragon #365) are the primary magical support that blast their enemies with an array of damaging spells.
Dragonborn In the Battlefield
To a dragonborn, honor is more important than life itself. First and foremost, honor is tied to battlefield conduct. Adversaries should be treated with courtesy and respect, even if they are bitter enemies. Caution and discretion are key to a warrior’s survival, but fear is a disease and cowardice is a moral failing. (PHB, pg. 35)
The battlefield is a very sacred ground for the dragonborn. It is a stage where they could display the fruits of their tireless effort in training and a moral high ground. Dragonborn ferocity in combat is well known but they are by no means bloodthristy. Dragonborn soliders and commanders know when there are times to stop pressing forward and aid any comrades in dire situations.
Dragonborn honor dictates that they must accept any surrender from the enemy and prisoners of war are treated with respect during their captivity. Looting of the dead is forbidden but capturing of supplies is acceptable.
If there is any fear that can be found among the dragonborn is the fear of defeat. A Dragonborn's honor requires them to rise against a challenge as long as success can be achieved with calculated risk and good judgment. Once they have promised that victory can be attained, it becomes a test of their honor. Their pride gives them an inherent fear of failure which is taken as a sign of losing one's honor or failing to meet the responsibilities of keeping ones promise. A dragonborn general would never submit to defeat and would withdraw to fight another day if necessary or fight to the death if cornered.
However such fears can also work in the favor of dragonborn commanders since it is usually when the odds are turning against them that the dragonborn spirit would become more resolved and fight ever more harder. It is actually rare to see a dragonborn army break out of sheer horror or poor morale unless their most reasonable discretion tell them otherwise.
Tactics & Strategy
Dragonborn employ intense and straightforward tactics, aiming at taking enemies out of an ongoing clash. Their military leaders facilitate efficient butchery. Arcanists pour on damage, their attacks resembling dragon breath weapons. (Ecology of the Dragonborn, Dragon #365)
Dragonborns are not afraid of direct confrontations. In fact, they revel in them. The only maneuver that a dragonborn general knows is one that will lead his army to the opposing army in the shortest route possible. A battle with a dragonborn army is bound to be a brutal fest of steel, talons and flame sooner or later.
Dragonborn honor don't usually allow dishonorable methods such as assassinations, subterfuge or preemptive strikes before actual combat unless it can be justified as part of a strategy to balance the odds for the dragonborn army when they meet on the battlefield.
Champions are always at the forefront of the army when battle commence. Their tactic is usually to fly straight into the opposing army and cause havoc among the lower ranks of the enemy with their flourishing blade work. However, the main job of the Champion is to find a suitable challenge (usually a commanding officer of the enemy) and take them out.
Gladiators are the second wave of shock troops but their lack of mobility usually leaves them on the front line slashing through the enemy until either is slain. Dragonborn Elementalists provide magical support as artillery and magic is wielded like a weapon in the hands of a warrior.
A tactical advantage of dragonborn armies is that each dragonborn are born with the elemental core to breath out a deadly burst of energy when they are wounded in combat. This advantage is not used blatantly and not without the coordination of a commander that can maximize the damage caused by these breath weapons.
The standard arsenal of a dragonborn army is a steel blade. Every dragonborn soldier is armed with a longsword while gladiators and champions usually carry a bastard sword. Champions are also known to carry the Tratnyr (Adventurers' Vault, pg 10), a winged spear that can be thrown as a javelin from the air but are just as effective when used in melee.
Dragonborn commandants sometimes ride into battle on rage drakes (MM, pg 92) which acts as a vicious mount especially when it gets bloodied in combat. Rage drakes also accompany units of dragonborn soldiers not as mounts but simply as a war beast.
Dragonborns have also developed fortification armor (Adventurers' Vault, pg 45) that are know to be impervious towards deadly attacks that could potentially save the life of a scale armor clad soldier or a plate armored champion.
Magical items that are also found in the dragonborn weaponry are Dragonborn Greaves (Adventurers' Vault, pg 128), Wyrmtouched Amulet (Adventurers' Vault, pg 155) and the most prized, Ring of the Dragonborn Emperor (Adventurers' Vault 161).