Paladin is a defensive melee warrior. He uses swords and blunts with shield and heavy armor. He can stun and gets a large palette of skills specifically against undead.
Like all pure tank classes, he has Aggression and Hate Aura to attract mobs to focus their attacks on him (instead of on other party members), and he has Shield Fortress and Ultimate Defense to increase his defense values, and Deflect Arrow to make bow attacks much less efficient on him. He also has the passive skills Final Fortress to increase p.def with falling hp, and Shield Mastery to improve the effectivity of shields.
Like the Dark Avenger, he has Shield Stun and Majesty.
He can protect himself from incoming attacks from all directions using Aegis Stance. He can heal himself using Holy Blessing.
Against Undead, he gets better fight values with the passive skills Holy Armor and Holy Blade, and the active skills Holy Strike and Sanctuary.
 Key Skills
Format: Name (Max. Level) - Description (Level[+Updates]/Next Level ...)
- Aegis Stance (1) - Lowers shield success rate for protection from all directions. (46)
- Angelic Icon (3) - By the will of your God, your fighting ability with one-handed swords significantly increases. While in use, the effects of HP regeneration magic significantly decreases. This skill is only available when your HP is at 30 percent or lower
- Aggression (49) - Provokes opponent's desire to attack. (24+3/28+3/32+3/36+3/40+3/43+3/46+3/49+3/52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Deflect Arrow (4) - Increases defense against bow attacks. (24/32/43/49)
- Hate Aura (37) - Provokes your opponent to attack. (40+3/43+3/46+3/49+3/52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Holy Blessing (37) - Heals self. (40+3/43+3/46+3/49+3/52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Holy Strike (26) - Inflicts damage to undead monsters. (46+2/49+2/52+2/55+2/58+2/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Iron Will (3) - Temporarily increases M. Def. (43/49/55)
- Majesty (3) - Temporarily decreases Evasion and increases P. Def. (20/40/58)
- Remedy (3) - Cures own bleeding. (40/49/62)
- Shackle(10) - Provokes an enemy to attack and then temporarily puts them into a held state. The target cannot be affected by any additional hold attacks while the effect lasts.(55....74)
- Sacrifice (25) - Recovers HP sacrificing own powers. (52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Sanctuary (11) - Instantly reduces P. Atk. of surrounding undead monsters. (52/55/58/60/62/64/66/68/70/72/74)
- Shield Fortress (6) - Increases personal shield defense rate. Continuously consumes MP. (64/66/68/70/72/74)
- Shield Stun (52) - Throws target into a state of shock. (20+3/24+3/28+3/32+3/36+3/40+3/43+3/46+3/49+3/52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Relax (1) - Regeneration when sitting. (5)
- Ultimate Defense (2) - Instantly increases P. Def. and M. Def. significantly. User must remain still while it takes effect. (20/46)
- Armor Mastery (5) - Increases P.def for heavy / P.def and Evasion for light armor. (5/10+2/15+2)
- Final Fortress (11) - Automatically increases P. Def. when HP level falls. (52/55/58/60/62/64/66/68/70/72/72)
- Focus Mind (6) - Increases one's MP Recovery Speed. (36/43/49/55/64/72)
- Heavy Armor Mastery (52) - Increases P.def. with Heavy Armor. (20+3/24+3/28+3/32+3/36+3/40+3/43+3/46+3/49+3/52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Holy Armor (2) - Increases defense against undead monsters. (40/46)
- Holy Blade (1) - Attacks with sacred power. (43)
- Shield Mastery (4) - Shield defense rate increases. (20/28/40/52)
- Sword Blunt Mastery (45) - Increases P. Atk. for Swords and Blunts. (20/24/28+2/32+2/36+2/40+3/43+3/46+3/49+3/52+3/55+3/58+3/60+2/62+2/64+2/66+2/68+2/70+2/72+2/74+2)
- Weapon Mastery (3) - Attack power increases. (5/10/15)
- Divine Heal (9) - Recovers one's HP. (28+3/32+3/36+3)
- Drain Health (13) - Absorbs HP. (20+2/24+2/28+3/32+3/36+3)
- Power Strike (9) - Extra Damage on target. Sword/Blunt only. Over-hit available. (5+3/10+3/15+3)
Naturally, the Paladin tries to get the best one-handed sword or blunt and shield of the level.
C-grade: Samurai Longsword / Yaksa Mace, B-Grade: Sword of Damascus / Art of Battle Axe / Deadman's Glory, A-Grade: Dark Legion's Edge / Elysian Axe.
On c-grade, the full plate armor gives another nice bonus to the shield skills. On b-grade, the Avadon and Doom Sets are even much better. The boni of the a-grade Dark Crystal set on shields is amusingly less good, but the improved p.def and good immunities make up for this.
Paladins need the following spellbooks: Level 40: Holy Blessing, Remedy; Level 43: Iron Will; Level 46: Holy Strike; Level 52: Sacrifice.
Tanks are obviously quite easy to solo, only a little boring maybe.
Inside groups, they activate their Hate Aura and keep mobs attacking them instead of the damage dealers.
Best group for a tank is of course a mix of buffers, a large number of damage dealers and nukers, and maybe a healer. Best buffer for the tank himself is a Prophet who avoids buffing 'Berserker Spirit' to the tank, plus an Elven Elder - because of their Agility and Bless shield buffs, but they can also give mana and healing and raise almost as good as a Bishop - and a Swordsinger. Of course the other party members will prefer other buffer classes which optimize offense instead of defense. Most anoying for the tank is probably an Overlord because they buff Berzerker Spirit - on everyone of the alliance, so you don't even have to be in party with the Overlord to receive this buff.
The Paladin is optimal for battling undeads, which specifically appear en masse in some dungeons as well as many other places, for example Executioneer Ground, Dragon Valley, Devastated Castle, or TOI.