The Gladiator is one of the primary tanking classes in Final Fantasy XIV: A Realm Reborn. They wield a one-hand Sward and an off-hand Shield. A gladiator's main focus in tanking is to mitigate damage through blocking with shield and to use skills like 'Flash' that will hit all enemies within 10 yalms.
Leveling a GLD to 30 and a CNJ to 15 will unlock the main job for Gladiators called Paladin (PLD). Paladins are essentially holy gladiators with more magic capabilities to help retain enmity. They will allow higher HP and Defense ratings, among some abilities that will reduce damage. The only real flaw of using PLD over just GLD is that they will deal less damage
Icon Level Action Description Cost Duration Cooldown 1 1 Fast Blade An instant attack with a potency of 150 70 TP --- 02.5s 2 2 Rampart A defensive cooldown that reduces damage taken by 10% 0 20s 90s 3 4 Savage Blade Delivers an attack with a potency of 100 and increases enmity. Combos with 'Fast Blade' for potency of 200 60 TP --- 02.5s 4 6 Fight or Flight An offensive cooldown that increases Physical damage dealt by 30%. --- 20s 180s 5 8 Flash The only action that generates enmity that targets enemies (within 5 yalms) and deals no damage. It generates the same amount of enmity to all targets and is not divided. 212 MP --- 02.5s 6 10 Convalascence An instant cooldown that increases HP restored by spells or actions by 20%. 0 20s 120s 7 12 Riot Blade Delivers an attack with a potency of 100. Combos with 'Fast Blade' for potency of 230. Restores MP if used in a combo. 100 TP --- 02.5s 8 15 Shield Lob Delivers an attack on target (within 15 yalms) with a potency of 120 and increases enmity. 120 TP --- 02.5s 9 18 Shield Bash Delivers an attack with a potency of 110 and stuns the target. 150 TP 03s 02.5s 10 22 Provoke Instantly increases your enmity to the top of target, so no matter how much enmity you have, once you cast 'Provoke' you will be instantly targeted. Can cast within a 25 yalm range. 0 --- 40s 11 26 Rage of Halone Delivers an attack with a potency of 100 and...
Gladiator/Paladin Class Guide
General overview of the GLD and PLD classes in FFXIV